| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Zheng Yan | 10596 | 52.78% | 29 | 5.72% |
| Qu Wenruo | 2831 | 14.10% | 71 | 14.00% |
| Chris Mason | 1793 | 8.93% | 123 | 24.26% |
| Josef Whiter | 1637 | 8.15% | 84 | 16.57% |
| Josef Bacik | 640 | 3.19% | 27 | 5.33% |
| David Sterba | 360 | 1.79% | 29 | 5.72% |
| Jeff Mahoney | 282 | 1.40% | 10 | 1.97% |
| Shilong Wang | 278 | 1.38% | 6 | 1.18% |
| Liu Bo | 262 | 1.31% | 14 | 2.76% |
| Nikolay Borisov | 191 | 0.95% | 18 | 3.55% |
| Filipe David Borba Manana | 178 | 0.89% | 19 | 3.75% |
| Boris Burkov | 161 | 0.80% | 2 | 0.39% |
| Christoph Hellwig | 126 | 0.63% | 5 | 0.99% |
| Li Dongyang | 99 | 0.49% | 1 | 0.20% |
| Miao Xie | 75 | 0.37% | 10 | 1.97% |
| Tsutomu Itoh | 64 | 0.32% | 5 | 0.99% |
| Balaji Rao | 62 | 0.31% | 1 | 0.20% |
| Omar Sandoval | 53 | 0.26% | 3 | 0.59% |
| Naohiro Aota | 48 | 0.24% | 4 | 0.79% |
| Zhao Lei | 45 | 0.22% | 2 | 0.39% |
| Adam Borowski | 43 | 0.21% | 1 | 0.20% |
| Li Zefan | 41 | 0.20% | 2 | 0.39% |
| Xiaoguang Wang | 38 | 0.19% | 2 | 0.39% |
| David Woodhouse | 29 | 0.14% | 4 | 0.79% |
| Sage Weil | 19 | 0.09% | 3 | 0.59% |
| Jan Schmidt | 18 | 0.09% | 2 | 0.39% |
| Yan Zheng | 14 | 0.07% | 3 | 0.59% |
| Anand Jain | 14 | 0.07% | 4 | 0.79% |
| Daniel J Blueman | 12 | 0.06% | 1 | 0.20% |
| Matthew Wilcox | 10 | 0.05% | 2 | 0.39% |
| Xiyu Yang | 10 | 0.05% | 1 | 0.20% |
| Zixuan Fu | 9 | 0.04% | 1 | 0.20% |
| Johannes Thumshirn | 5 | 0.02% | 2 | 0.39% |
| Joe Perches | 4 | 0.02% | 1 | 0.20% |
| Pan Bian | 4 | 0.02% | 1 | 0.20% |
| Américo Wang | 4 | 0.02% | 1 | 0.20% |
| Dulshani Gunawardhana | 3 | 0.01% | 1 | 0.20% |
| Sven Wegener | 2 | 0.01% | 1 | 0.20% |
| Arne Jansen | 2 | 0.01% | 1 | 0.20% |
| Linus Torvalds (pre-git) | 2 | 0.01% | 1 | 0.20% |
| Frank Holton | 2 | 0.01% | 1 | 0.20% |
| Kirill A. Shutemov | 1 | 0.00% | 1 | 0.20% |
| Lu Fengqi | 1 | 0.00% | 1 | 0.20% |
| Linus Torvalds | 1 | 0.00% | 1 | 0.20% |
| Miguel | 1 | 0.00% | 1 | 0.20% |
| katrinzhou | 1 | 0.00% | 1 | 0.20% |
| Zach Brown | 1 | 0.00% | 1 | 0.20% |
| Andrea Gelmini | 1 | 0.00% | 1 | 0.20% |
| Nicholas D Steeves | 1 | 0.00% | 1 | 0.20% |
| Total | 20074 | 507 |
// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2009 Oracle. All rights reserved. */ #include <linux/sched.h> #include <linux/pagemap.h> #include <linux/writeback.h> #include <linux/blkdev.h> #include <linux/rbtree.h> #include <linux/slab.h> #include <linux/error-injection.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "volumes.h" #include "locking.h" #include "btrfs_inode.h" #include "async-thread.h" #include "free-space-cache.h" #include "qgroup.h" #include "print-tree.h" #include "delalloc-space.h" #include "block-group.h" #include "backref.h" #include "misc.h" #include "subpage.h" #include "zoned.h" #include "inode-item.h" #include "space-info.h" #include "fs.h" #include "accessors.h" #include "extent-tree.h" #include "root-tree.h" #include "file-item.h" #include "relocation.h" #include "super.h" #include "tree-checker.h" /* * Relocation overview * * [What does relocation do] * * The objective of relocation is to relocate all extents of the target block * group to other block groups. * This is utilized by resize (shrink only), profile converting, compacting * space, or balance routine to spread chunks over devices. * * Before | After * ------------------------------------------------------------------ * BG A: 10 data extents | BG A: deleted * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated) * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated) * * [How does relocation work] * * 1. Mark the target block group read-only * New extents won't be allocated from the target block group. * * 2.1 Record each extent in the target block group * To build a proper map of extents to be relocated. * * 2.2 Build data reloc tree and reloc trees * Data reloc tree will contain an inode, recording all newly relocated * data extents. * There will be only one data reloc tree for one data block group. * * Reloc tree will be a special snapshot of its source tree, containing * relocated tree blocks. * Each tree referring to a tree block in target block group will get its * reloc tree built. * * 2.3 Swap source tree with its corresponding reloc tree * Each involved tree only refers to new extents after swap. * * 3. Cleanup reloc trees and data reloc tree. * As old extents in the target block group are still referenced by reloc * trees, we need to clean them up before really freeing the target block * group. * * The main complexity is in steps 2.2 and 2.3. * * The entry point of relocation is relocate_block_group() function. */ #define RELOCATION_RESERVED_NODES 256 /* * map address of tree root to tree */ struct mapping_node { struct { struct rb_node rb_node; u64 bytenr; }; /* Use rb_simle_node for search/insert */ void *data; }; struct mapping_tree { struct rb_root rb_root; spinlock_t lock; }; /* * present a tree block to process */ struct tree_block { struct { struct rb_node rb_node; u64 bytenr; }; /* Use rb_simple_node for search/insert */ u64 owner; struct btrfs_key key; u8 level; bool key_ready; }; #define MAX_EXTENTS 128 struct file_extent_cluster { u64 start; u64 end; u64 boundary[MAX_EXTENTS]; unsigned int nr; u64 owning_root; }; /* Stages of data relocation. */ enum reloc_stage { MOVE_DATA_EXTENTS, UPDATE_DATA_PTRS }; struct reloc_control { /* block group to relocate */ struct btrfs_block_group *block_group; /* extent tree */ struct btrfs_root *extent_root; /* inode for moving data */ struct inode *data_inode; struct btrfs_block_rsv *block_rsv; struct btrfs_backref_cache backref_cache; struct file_extent_cluster cluster; /* tree blocks have been processed */ struct extent_io_tree processed_blocks; /* map start of tree root to corresponding reloc tree */ struct mapping_tree reloc_root_tree; /* list of reloc trees */ struct list_head reloc_roots; /* list of subvolume trees that get relocated */ struct list_head dirty_subvol_roots; /* size of metadata reservation for merging reloc trees */ u64 merging_rsv_size; /* size of relocated tree nodes */ u64 nodes_relocated; /* reserved size for block group relocation*/ u64 reserved_bytes; u64 search_start; u64 extents_found; enum reloc_stage stage; bool create_reloc_tree; bool merge_reloc_tree; bool found_file_extent; }; static void mark_block_processed(struct reloc_control *rc, struct btrfs_backref_node *node) { u32 blocksize; if (node->level == 0 || in_range(node->bytenr, rc->block_group->start, rc->block_group->length)) { blocksize = rc->extent_root->fs_info->nodesize; set_extent_bit(&rc->processed_blocks, node->bytenr, node->bytenr + blocksize - 1, EXTENT_DIRTY, NULL); } node->processed = 1; } /* * walk up backref nodes until reach node presents tree root */ static struct btrfs_backref_node *walk_up_backref( struct btrfs_backref_node *node, struct btrfs_backref_edge *edges[], int *index) { struct btrfs_backref_edge *edge; int idx = *index; while (!list_empty(&node->upper)) { edge = list_entry(node->upper.next, struct btrfs_backref_edge, list[LOWER]); edges[idx++] = edge; node = edge->node[UPPER]; } BUG_ON(node->detached); *index = idx; return node; } /* * walk down backref nodes to find start of next reference path */ static struct btrfs_backref_node *walk_down_backref( struct btrfs_backref_edge *edges[], int *index) { struct btrfs_backref_edge *edge; struct btrfs_backref_node *lower; int idx = *index; while (idx > 0) { edge = edges[idx - 1]; lower = edge->node[LOWER]; if (list_is_last(&edge->list[LOWER], &lower->upper)) { idx--; continue; } edge = list_entry(edge->list[LOWER].next, struct btrfs_backref_edge, list[LOWER]); edges[idx - 1] = edge; *index = idx; return edge->node[UPPER]; } *index = 0; return NULL; } static void update_backref_node(struct btrfs_backref_cache *cache, struct btrfs_backref_node *node, u64 bytenr) { struct rb_node *rb_node; rb_erase(&node->rb_node, &cache->rb_root); node->bytenr = bytenr; rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node); if (rb_node) btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST); } /* * update backref cache after a transaction commit */ static int update_backref_cache(struct btrfs_trans_handle *trans, struct btrfs_backref_cache *cache) { struct btrfs_backref_node *node; int level = 0; if (cache->last_trans == 0) { cache->last_trans = trans->transid; return 0; } if (cache->last_trans == trans->transid) return 0; /* * detached nodes are used to avoid unnecessary backref * lookup. transaction commit changes the extent tree. * so the detached nodes are no longer useful. */ while (!list_empty(&cache->detached)) { node = list_entry(cache->detached.next, struct btrfs_backref_node, list); btrfs_backref_cleanup_node(cache, node); } while (!list_empty(&cache->changed)) { node = list_entry(cache->changed.next, struct btrfs_backref_node, list); list_del_init(&node->list); BUG_ON(node->pending); update_backref_node(cache, node, node->new_bytenr); } /* * some nodes can be left in the pending list if there were * errors during processing the pending nodes. */ for (level = 0; level < BTRFS_MAX_LEVEL; level++) { list_for_each_entry(node, &cache->pending[level], list) { BUG_ON(!node->pending); if (node->bytenr == node->new_bytenr) continue; update_backref_node(cache, node, node->new_bytenr); } } cache->last_trans = 0; return 1; } static bool reloc_root_is_dead(const struct btrfs_root *root) { /* * Pair with set_bit/clear_bit in clean_dirty_subvols and * btrfs_update_reloc_root. We need to see the updated bit before * trying to access reloc_root */ smp_rmb(); if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state)) return true; return false; } /* * Check if this subvolume tree has valid reloc tree. * * Reloc tree after swap is considered dead, thus not considered as valid. * This is enough for most callers, as they don't distinguish dead reloc root * from no reloc root. But btrfs_should_ignore_reloc_root() below is a * special case. */ static bool have_reloc_root(const struct btrfs_root *root) { if (reloc_root_is_dead(root)) return false; if (!root->reloc_root) return false; return true; } bool btrfs_should_ignore_reloc_root(const struct btrfs_root *root) { struct btrfs_root *reloc_root; if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) return false; /* This root has been merged with its reloc tree, we can ignore it */ if (reloc_root_is_dead(root)) return true; reloc_root = root->reloc_root; if (!reloc_root) return false; if (btrfs_header_generation(reloc_root->commit_root) == root->fs_info->running_transaction->transid) return false; /* * If there is reloc tree and it was created in previous transaction * backref lookup can find the reloc tree, so backref node for the fs * tree root is useless for relocation. */ return true; } /* * find reloc tree by address of tree root */ struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr) { struct reloc_control *rc = fs_info->reloc_ctl; struct rb_node *rb_node; struct mapping_node *node; struct btrfs_root *root = NULL; ASSERT(rc); spin_lock(&rc->reloc_root_tree.lock); rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr); if (rb_node) { node = rb_entry(rb_node, struct mapping_node, rb_node); root = node->data; } spin_unlock(&rc->reloc_root_tree.lock); return btrfs_grab_root(root); } /* * For useless nodes, do two major clean ups: * * - Cleanup the children edges and nodes * If child node is also orphan (no parent) during cleanup, then the child * node will also be cleaned up. * * - Freeing up leaves (level 0), keeps nodes detached * For nodes, the node is still cached as "detached" * * Return false if @node is not in the @useless_nodes list. * Return true if @node is in the @useless_nodes list. */ static bool handle_useless_nodes(struct reloc_control *rc, struct btrfs_backref_node *node) { struct btrfs_backref_cache *cache = &rc->backref_cache; struct list_head *useless_node = &cache->useless_node; bool ret = false; while (!list_empty(useless_node)) { struct btrfs_backref_node *cur; cur = list_first_entry(useless_node, struct btrfs_backref_node, list); list_del_init(&cur->list); /* Only tree root nodes can be added to @useless_nodes */ ASSERT(list_empty(&cur->upper)); if (cur == node) ret = true; /* The node is the lowest node */ if (cur->lowest) { list_del_init(&cur->lower); cur->lowest = 0; } /* Cleanup the lower edges */ while (!list_empty(&cur->lower)) { struct btrfs_backref_edge *edge; struct btrfs_backref_node *lower; edge = list_entry(cur->lower.next, struct btrfs_backref_edge, list[UPPER]); list_del(&edge->list[UPPER]); list_del(&edge->list[LOWER]); lower = edge->node[LOWER]; btrfs_backref_free_edge(cache, edge); /* Child node is also orphan, queue for cleanup */ if (list_empty(&lower->upper)) list_add(&lower->list, useless_node); } /* Mark this block processed for relocation */ mark_block_processed(rc, cur); /* * Backref nodes for tree leaves are deleted from the cache. * Backref nodes for upper level tree blocks are left in the * cache to avoid unnecessary backref lookup. */ if (cur->level > 0) { list_add(&cur->list, &cache->detached); cur->detached = 1; } else { rb_erase(&cur->rb_node, &cache->rb_root); btrfs_backref_free_node(cache, cur); } } return ret; } /* * Build backref tree for a given tree block. Root of the backref tree * corresponds the tree block, leaves of the backref tree correspond roots of * b-trees that reference the tree block. * * The basic idea of this function is check backrefs of a given block to find * upper level blocks that reference the block, and then check backrefs of * these upper level blocks recursively. The recursion stops when tree root is * reached or backrefs for the block is cached. * * NOTE: if we find that backrefs for a block are cached, we know backrefs for * all upper level blocks that directly/indirectly reference the block are also * cached. */ static noinline_for_stack struct btrfs_backref_node *build_backref_tree( struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_key *node_key, int level, u64 bytenr) { struct btrfs_backref_iter *iter; struct btrfs_backref_cache *cache = &rc->backref_cache; /* For searching parent of TREE_BLOCK_REF */ struct btrfs_path *path; struct btrfs_backref_node *cur; struct btrfs_backref_node *node = NULL; struct btrfs_backref_edge *edge; int ret; int err = 0; iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info); if (!iter) return ERR_PTR(-ENOMEM); path = btrfs_alloc_path(); if (!path) { err = -ENOMEM; goto out; } node = btrfs_backref_alloc_node(cache, bytenr, level); if (!node) { err = -ENOMEM; goto out; } node->lowest = 1; cur = node; /* Breadth-first search to build backref cache */ do { ret = btrfs_backref_add_tree_node(trans, cache, path, iter, node_key, cur); if (ret < 0) { err = ret; goto out; } edge = list_first_entry_or_null(&cache->pending_edge, struct btrfs_backref_edge, list[UPPER]); /* * The pending list isn't empty, take the first block to * process */ if (edge) { list_del_init(&edge->list[UPPER]); cur = edge->node[UPPER]; } } while (edge); /* Finish the upper linkage of newly added edges/nodes */ ret = btrfs_backref_finish_upper_links(cache, node); if (ret < 0) { err = ret; goto out; } if (handle_useless_nodes(rc, node)) node = NULL; out: btrfs_backref_iter_free(iter); btrfs_free_path(path); if (err) { btrfs_backref_error_cleanup(cache, node); return ERR_PTR(err); } ASSERT(!node || !node->detached); ASSERT(list_empty(&cache->useless_node) && list_empty(&cache->pending_edge)); return node; } /* * helper to add backref node for the newly created snapshot. * the backref node is created by cloning backref node that * corresponds to root of source tree */ static int clone_backref_node(struct btrfs_trans_handle *trans, struct reloc_control *rc, const struct btrfs_root *src, struct btrfs_root *dest) { struct btrfs_root *reloc_root = src->reloc_root; struct btrfs_backref_cache *cache = &rc->backref_cache; struct btrfs_backref_node *node = NULL; struct btrfs_backref_node *new_node; struct btrfs_backref_edge *edge; struct btrfs_backref_edge *new_edge; struct rb_node *rb_node; if (cache->last_trans > 0) update_backref_cache(trans, cache); rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start); if (rb_node) { node = rb_entry(rb_node, struct btrfs_backref_node, rb_node); if (node->detached) node = NULL; else BUG_ON(node->new_bytenr != reloc_root->node->start); } if (!node) { rb_node = rb_simple_search(&cache->rb_root, reloc_root->commit_root->start); if (rb_node) { node = rb_entry(rb_node, struct btrfs_backref_node, rb_node); BUG_ON(node->detached); } } if (!node) return 0; new_node = btrfs_backref_alloc_node(cache, dest->node->start, node->level); if (!new_node) return -ENOMEM; new_node->lowest = node->lowest; new_node->checked = 1; new_node->root = btrfs_grab_root(dest); ASSERT(new_node->root); if (!node->lowest) { list_for_each_entry(edge, &node->lower, list[UPPER]) { new_edge = btrfs_backref_alloc_edge(cache); if (!new_edge) goto fail; btrfs_backref_link_edge(new_edge, edge->node[LOWER], new_node, LINK_UPPER); } } else { list_add_tail(&new_node->lower, &cache->leaves); } rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr, &new_node->rb_node); if (rb_node) btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST); if (!new_node->lowest) { list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) { list_add_tail(&new_edge->list[LOWER], &new_edge->node[LOWER]->upper); } } return 0; fail: while (!list_empty(&new_node->lower)) { new_edge = list_entry(new_node->lower.next, struct btrfs_backref_edge, list[UPPER]); list_del(&new_edge->list[UPPER]); btrfs_backref_free_edge(cache, new_edge); } btrfs_backref_free_node(cache, new_node); return -ENOMEM; } /* * helper to add 'address of tree root -> reloc tree' mapping */ static int __add_reloc_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct rb_node *rb_node; struct mapping_node *node; struct reloc_control *rc = fs_info->reloc_ctl; node = kmalloc(sizeof(*node), GFP_NOFS); if (!node) return -ENOMEM; node->bytenr = root->commit_root->start; node->data = root; spin_lock(&rc->reloc_root_tree.lock); rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root, node->bytenr, &node->rb_node); spin_unlock(&rc->reloc_root_tree.lock); if (rb_node) { btrfs_err(fs_info, "Duplicate root found for start=%llu while inserting into relocation tree", node->bytenr); return -EEXIST; } list_add_tail(&root->root_list, &rc->reloc_roots); return 0; } /* * helper to delete the 'address of tree root -> reloc tree' * mapping */ static void __del_reloc_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct rb_node *rb_node; struct mapping_node *node = NULL; struct reloc_control *rc = fs_info->reloc_ctl; bool put_ref = false; if (rc && root->node) { spin_lock(&rc->reloc_root_tree.lock); rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, root->commit_root->start); if (rb_node) { node = rb_entry(rb_node, struct mapping_node, rb_node); rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root); RB_CLEAR_NODE(&node->rb_node); } spin_unlock(&rc->reloc_root_tree.lock); ASSERT(!node || (struct btrfs_root *)node->data == root); } /* * We only put the reloc root here if it's on the list. There's a lot * of places where the pattern is to splice the rc->reloc_roots, process * the reloc roots, and then add the reloc root back onto * rc->reloc_roots. If we call __del_reloc_root while it's off of the * list we don't want the reference being dropped, because the guy * messing with the list is in charge of the reference. */ spin_lock(&fs_info->trans_lock); if (!list_empty(&root->root_list)) { put_ref = true; list_del_init(&root->root_list); } spin_unlock(&fs_info->trans_lock); if (put_ref) btrfs_put_root(root); kfree(node); } /* * helper to update the 'address of tree root -> reloc tree' * mapping */ static int __update_reloc_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct rb_node *rb_node; struct mapping_node *node = NULL; struct reloc_control *rc = fs_info->reloc_ctl; spin_lock(&rc->reloc_root_tree.lock); rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, root->commit_root->start); if (rb_node) { node = rb_entry(rb_node, struct mapping_node, rb_node); rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root); } spin_unlock(&rc->reloc_root_tree.lock); if (!node) return 0; BUG_ON((struct btrfs_root *)node->data != root); spin_lock(&rc->reloc_root_tree.lock); node->bytenr = root->node->start; rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root, node->bytenr, &node->rb_node); spin_unlock(&rc->reloc_root_tree.lock); if (rb_node) btrfs_backref_panic(fs_info, node->bytenr, -EEXIST); return 0; } static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 objectid) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_root *reloc_root; struct extent_buffer *eb; struct btrfs_root_item *root_item; struct btrfs_key root_key; int ret = 0; bool must_abort = false; root_item = kmalloc(sizeof(*root_item), GFP_NOFS); if (!root_item) return ERR_PTR(-ENOMEM); root_key.objectid = BTRFS_TREE_RELOC_OBJECTID; root_key.type = BTRFS_ROOT_ITEM_KEY; root_key.offset = objectid; if (root->root_key.objectid == objectid) { u64 commit_root_gen; /* called by btrfs_init_reloc_root */ ret = btrfs_copy_root(trans, root, root->commit_root, &eb, BTRFS_TREE_RELOC_OBJECTID); if (ret) goto fail; /* * Set the last_snapshot field to the generation of the commit * root - like this ctree.c:btrfs_block_can_be_shared() behaves * correctly (returns true) when the relocation root is created * either inside the critical section of a transaction commit * (through transaction.c:qgroup_account_snapshot()) and when * it's created before the transaction commit is started. */ commit_root_gen = btrfs_header_generation(root->commit_root); btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen); } else { /* * called by btrfs_reloc_post_snapshot_hook. * the source tree is a reloc tree, all tree blocks * modified after it was created have RELOC flag * set in their headers. so it's OK to not update * the 'last_snapshot'. */ ret = btrfs_copy_root(trans, root, root->node, &eb, BTRFS_TREE_RELOC_OBJECTID); if (ret) goto fail; } /* * We have changed references at this point, we must abort the * transaction if anything fails. */ must_abort = true; memcpy(root_item, &root->root_item, sizeof(*root_item)); btrfs_set_root_bytenr(root_item, eb->start); btrfs_set_root_level(root_item, btrfs_header_level(eb)); btrfs_set_root_generation(root_item, trans->transid); if (root->root_key.objectid == objectid) { btrfs_set_root_refs(root_item, 0); memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key)); btrfs_set_root_drop_level(root_item, 0); } btrfs_tree_unlock(eb); free_extent_buffer(eb); ret = btrfs_insert_root(trans, fs_info->tree_root, &root_key, root_item); if (ret) goto fail; kfree(root_item); reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key); if (IS_ERR(reloc_root)) { ret = PTR_ERR(reloc_root); goto abort; } set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state); reloc_root->last_trans = trans->transid; return reloc_root; fail: kfree(root_item); abort: if (must_abort) btrfs_abort_transaction(trans, ret); return ERR_PTR(ret); } /* * create reloc tree for a given fs tree. reloc tree is just a * snapshot of the fs tree with special root objectid. * * The reloc_root comes out of here with two references, one for * root->reloc_root, and another for being on the rc->reloc_roots list. */ int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_root *reloc_root; struct reloc_control *rc = fs_info->reloc_ctl; struct btrfs_block_rsv *rsv; int clear_rsv = 0; int ret; if (!rc) return 0; /* * The subvolume has reloc tree but the swap is finished, no need to * create/update the dead reloc tree */ if (reloc_root_is_dead(root)) return 0; /* * This is subtle but important. We do not do * record_root_in_transaction for reloc roots, instead we record their * corresponding fs root, and then here we update the last trans for the * reloc root. This means that we have to do this for the entire life * of the reloc root, regardless of which stage of the relocation we are * in. */ if (root->reloc_root) { reloc_root = root->reloc_root; reloc_root->last_trans = trans->transid; return 0; } /* * We are merging reloc roots, we do not need new reloc trees. Also * reloc trees never need their own reloc tree. */ if (!rc->create_reloc_tree || root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) return 0; if (!trans->reloc_reserved) { rsv = trans->block_rsv; trans->block_rsv = rc->block_rsv; clear_rsv = 1; } reloc_root = create_reloc_root(trans, root, root->root_key.objectid); if (clear_rsv) trans->block_rsv = rsv; if (IS_ERR(reloc_root)) return PTR_ERR(reloc_root); ret = __add_reloc_root(reloc_root); ASSERT(ret != -EEXIST); if (ret) { /* Pairs with create_reloc_root */ btrfs_put_root(reloc_root); return ret; } root->reloc_root = btrfs_grab_root(reloc_root); return 0; } /* * update root item of reloc tree */ int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_root *reloc_root; struct btrfs_root_item *root_item; int ret; if (!have_reloc_root(root)) return 0; reloc_root = root->reloc_root; root_item = &reloc_root->root_item; /* * We are probably ok here, but __del_reloc_root() will drop its ref of * the root. We have the ref for root->reloc_root, but just in case * hold it while we update the reloc root. */ btrfs_grab_root(reloc_root); /* root->reloc_root will stay until current relocation finished */ if (fs_info->reloc_ctl->merge_reloc_tree && btrfs_root_refs(root_item) == 0) { set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state); /* * Mark the tree as dead before we change reloc_root so * have_reloc_root will not touch it from now on. */ smp_wmb(); __del_reloc_root(reloc_root); } if (reloc_root->commit_root != reloc_root->node) { __update_reloc_root(reloc_root); btrfs_set_root_node(root_item, reloc_root->node); free_extent_buffer(reloc_root->commit_root); reloc_root->commit_root = btrfs_root_node(reloc_root); } ret = btrfs_update_root(trans, fs_info->tree_root, &reloc_root->root_key, root_item); btrfs_put_root(reloc_root); return ret; } /* * helper to find first cached inode with inode number >= objectid * in a subvolume */ static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid) { struct rb_node *node; struct rb_node *prev; struct btrfs_inode *entry; struct inode *inode; spin_lock(&root->inode_lock); again: node = root->inode_tree.rb_node; prev = NULL; while (node) { prev = node; entry = rb_entry(node, struct btrfs_inode, rb_node); if (objectid < btrfs_ino(entry)) node = node->rb_left; else if (objectid > btrfs_ino(entry)) node = node->rb_right; else break; } if (!node) { while (prev) { entry = rb_entry(prev, struct btrfs_inode, rb_node); if (objectid <= btrfs_ino(entry)) { node = prev; break; } prev = rb_next(prev); } } while (node) { entry = rb_entry(node, struct btrfs_inode, rb_node); inode = igrab(&entry->vfs_inode); if (inode) { spin_unlock(&root->inode_lock); return inode; } objectid = btrfs_ino(entry) + 1; if (cond_resched_lock(&root->inode_lock)) goto again; node = rb_next(node); } spin_unlock(&root->inode_lock); return NULL; } /* * get new location of data */ static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr, u64 bytenr, u64 num_bytes) { struct btrfs_root *root = BTRFS_I(reloc_inode)->root; struct btrfs_path *path; struct btrfs_file_extent_item *fi; struct extent_buffer *leaf; int ret; path = btrfs_alloc_path(); if (!path) return -ENOMEM; bytenr -= BTRFS_I(reloc_inode)->index_cnt; ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0); if (ret < 0) goto out; if (ret > 0) { ret = -ENOENT; goto out; } leaf = path->nodes[0]; fi = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); BUG_ON(btrfs_file_extent_offset(leaf, fi) || btrfs_file_extent_compression(leaf, fi) || btrfs_file_extent_encryption(leaf, fi) || btrfs_file_extent_other_encoding(leaf, fi)); if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) { ret = -EINVAL; goto out; } *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); ret = 0; out: btrfs_free_path(path); return ret; } /* * update file extent items in the tree leaf to point to * the new locations. */ static noinline_for_stack int replace_file_extents(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_root *root, struct extent_buffer *leaf) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_key key; struct btrfs_file_extent_item *fi; struct inode *inode = NULL; u64 parent; u64 bytenr; u64 new_bytenr = 0; u64 num_bytes; u64 end; u32 nritems; u32 i; int ret = 0; int first = 1; int dirty = 0; if (rc->stage != UPDATE_DATA_PTRS) return 0; /* reloc trees always use full backref */ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) parent = leaf->start; else parent = 0; nritems = btrfs_header_nritems(leaf); for (i = 0; i < nritems; i++) { struct btrfs_ref ref = { 0 }; cond_resched(); btrfs_item_key_to_cpu(leaf, &key, i); if (key.type != BTRFS_EXTENT_DATA_KEY) continue; fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item); if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) continue; bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); if (bytenr == 0) continue; if (!in_range(bytenr, rc->block_group->start, rc->block_group->length)) continue; /* * if we are modifying block in fs tree, wait for read_folio * to complete and drop the extent cache */ if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { if (first) { inode = find_next_inode(root, key.objectid); first = 0; } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) { btrfs_add_delayed_iput(BTRFS_I(inode)); inode = find_next_inode(root, key.objectid); } if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) { struct extent_state *cached_state = NULL; end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); WARN_ON(!IS_ALIGNED(key.offset, fs_info->sectorsize)); WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize)); end--; ret = try_lock_extent(&BTRFS_I(inode)->io_tree, key.offset, end, &cached_state); if (!ret) continue; btrfs_drop_extent_map_range(BTRFS_I(inode), key.offset, end, true); unlock_extent(&BTRFS_I(inode)->io_tree, key.offset, end, &cached_state); } } ret = get_new_location(rc->data_inode, &new_bytenr, bytenr, num_bytes); if (ret) { /* * Don't have to abort since we've not changed anything * in the file extent yet. */ break; } btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr); dirty = 1; key.offset -= btrfs_file_extent_offset(leaf, fi); btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr, num_bytes, parent, root->root_key.objectid); btrfs_init_data_ref(&ref, btrfs_header_owner(leaf), key.objectid, key.offset, root->root_key.objectid, false); ret = btrfs_inc_extent_ref(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); break; } btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr, num_bytes, parent, root->root_key.objectid); btrfs_init_data_ref(&ref, btrfs_header_owner(leaf), key.objectid, key.offset, root->root_key.objectid, false); ret = btrfs_free_extent(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); break; } } if (dirty) btrfs_mark_buffer_dirty(trans, leaf); if (inode) btrfs_add_delayed_iput(BTRFS_I(inode)); return ret; } static noinline_for_stack int memcmp_node_keys(const struct extent_buffer *eb, int slot, const struct btrfs_path *path, int level) { struct btrfs_disk_key key1; struct btrfs_disk_key key2; btrfs_node_key(eb, &key1, slot); btrfs_node_key(path->nodes[level], &key2, path->slots[level]); return memcmp(&key1, &key2, sizeof(key1)); } /* * try to replace tree blocks in fs tree with the new blocks * in reloc tree. tree blocks haven't been modified since the * reloc tree was create can be replaced. * * if a block was replaced, level of the block + 1 is returned. * if no block got replaced, 0 is returned. if there are other * errors, a negative error number is returned. */ static noinline_for_stack int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_root *dest, struct btrfs_root *src, struct btrfs_path *path, struct btrfs_key *next_key, int lowest_level, int max_level) { struct btrfs_fs_info *fs_info = dest->fs_info; struct extent_buffer *eb; struct extent_buffer *parent; struct btrfs_ref ref = { 0 }; struct btrfs_key key; u64 old_bytenr; u64 new_bytenr; u64 old_ptr_gen; u64 new_ptr_gen; u64 last_snapshot; u32 blocksize; int cow = 0; int level; int ret; int slot; ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID); ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); last_snapshot = btrfs_root_last_snapshot(&src->root_item); again: slot = path->slots[lowest_level]; btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot); eb = btrfs_lock_root_node(dest); level = btrfs_header_level(eb); if (level < lowest_level) { btrfs_tree_unlock(eb); free_extent_buffer(eb); return 0; } if (cow) { ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb, BTRFS_NESTING_COW); if (ret) { btrfs_tree_unlock(eb); free_extent_buffer(eb); return ret; } } if (next_key) { next_key->objectid = (u64)-1; next_key->type = (u8)-1; next_key->offset = (u64)-1; } parent = eb; while (1) { level = btrfs_header_level(parent); ASSERT(level >= lowest_level); ret = btrfs_bin_search(parent, 0, &key, &slot); if (ret < 0) break; if (ret && slot > 0) slot--; if (next_key && slot + 1 < btrfs_header_nritems(parent)) btrfs_node_key_to_cpu(parent, next_key, slot + 1); old_bytenr = btrfs_node_blockptr(parent, slot); blocksize = fs_info->nodesize; old_ptr_gen = btrfs_node_ptr_generation(parent, slot); if (level <= max_level) { eb = path->nodes[level]; new_bytenr = btrfs_node_blockptr(eb, path->slots[level]); new_ptr_gen = btrfs_node_ptr_generation(eb, path->slots[level]); } else { new_bytenr = 0; new_ptr_gen = 0; } if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) { ret = level; break; } if (new_bytenr == 0 || old_ptr_gen > last_snapshot || memcmp_node_keys(parent, slot, path, level)) { if (level <= lowest_level) { ret = 0; break; } eb = btrfs_read_node_slot(parent, slot); if (IS_ERR(eb)) { ret = PTR_ERR(eb); break; } btrfs_tree_lock(eb); if (cow) { ret = btrfs_cow_block(trans, dest, eb, parent, slot, &eb, BTRFS_NESTING_COW); if (ret) { btrfs_tree_unlock(eb); free_extent_buffer(eb); break; } } btrfs_tree_unlock(parent); free_extent_buffer(parent); parent = eb; continue; } if (!cow) { btrfs_tree_unlock(parent); free_extent_buffer(parent); cow = 1; goto again; } btrfs_node_key_to_cpu(path->nodes[level], &key, path->slots[level]); btrfs_release_path(path); path->lowest_level = level; set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state); ret = btrfs_search_slot(trans, src, &key, path, 0, 1); clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state); path->lowest_level = 0; if (ret) { if (ret > 0) ret = -ENOENT; break; } /* * Info qgroup to trace both subtrees. * * We must trace both trees. * 1) Tree reloc subtree * If not traced, we will leak data numbers * 2) Fs subtree * If not traced, we will double count old data * * We don't scan the subtree right now, but only record * the swapped tree blocks. * The real subtree rescan is delayed until we have new * CoW on the subtree root node before transaction commit. */ ret = btrfs_qgroup_add_swapped_blocks(trans, dest, rc->block_group, parent, slot, path->nodes[level], path->slots[level], last_snapshot); if (ret < 0) break; /* * swap blocks in fs tree and reloc tree. */ btrfs_set_node_blockptr(parent, slot, new_bytenr); btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen); btrfs_mark_buffer_dirty(trans, parent); btrfs_set_node_blockptr(path->nodes[level], path->slots[level], old_bytenr); btrfs_set_node_ptr_generation(path->nodes[level], path->slots[level], old_ptr_gen); btrfs_mark_buffer_dirty(trans, path->nodes[level]); btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr, blocksize, path->nodes[level]->start, src->root_key.objectid); btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid, 0, true); ret = btrfs_inc_extent_ref(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); break; } btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr, blocksize, 0, dest->root_key.objectid); btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0, true); ret = btrfs_inc_extent_ref(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); break; } /* We don't know the real owning_root, use 0. */ btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr, blocksize, path->nodes[level]->start, 0); btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid, 0, true); ret = btrfs_free_extent(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); break; } /* We don't know the real owning_root, use 0. */ btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr, blocksize, 0, 0); btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0, true); ret = btrfs_free_extent(trans, &ref); if (ret) { btrfs_abort_transaction(trans, ret); break; } btrfs_unlock_up_safe(path, 0); ret = level; break; } btrfs_tree_unlock(parent); free_extent_buffer(parent); return ret; } /* * helper to find next relocated block in reloc tree */ static noinline_for_stack int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, int *level) { struct extent_buffer *eb; int i; u64 last_snapshot; u32 nritems; last_snapshot = btrfs_root_last_snapshot(&root->root_item); for (i = 0; i < *level; i++) { free_extent_buffer(path->nodes[i]); path->nodes[i] = NULL; } for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) { eb = path->nodes[i]; nritems = btrfs_header_nritems(eb); while (path->slots[i] + 1 < nritems) { path->slots[i]++; if (btrfs_node_ptr_generation(eb, path->slots[i]) <= last_snapshot) continue; *level = i; return 0; } free_extent_buffer(path->nodes[i]); path->nodes[i] = NULL; } return 1; } /* * walk down reloc tree to find relocated block of lowest level */ static noinline_for_stack int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, int *level) { struct extent_buffer *eb = NULL; int i; u64 ptr_gen = 0; u64 last_snapshot; u32 nritems; last_snapshot = btrfs_root_last_snapshot(&root->root_item); for (i = *level; i > 0; i--) { eb = path->nodes[i]; nritems = btrfs_header_nritems(eb); while (path->slots[i] < nritems) { ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]); if (ptr_gen > last_snapshot) break; path->slots[i]++; } if (path->slots[i] >= nritems) { if (i == *level) break; *level = i + 1; return 0; } if (i == 1) { *level = i; return 0; } eb = btrfs_read_node_slot(eb, path->slots[i]); if (IS_ERR(eb)) return PTR_ERR(eb); BUG_ON(btrfs_header_level(eb) != i - 1); path->nodes[i - 1] = eb; path->slots[i - 1] = 0; } return 1; } /* * invalidate extent cache for file extents whose key in range of * [min_key, max_key) */ static int invalidate_extent_cache(struct btrfs_root *root, const struct btrfs_key *min_key, const struct btrfs_key *max_key) { struct btrfs_fs_info *fs_info = root->fs_info; struct inode *inode = NULL; u64 objectid; u64 start, end; u64 ino; objectid = min_key->objectid; while (1) { struct extent_state *cached_state = NULL; cond_resched(); iput(inode); if (objectid > max_key->objectid) break; inode = find_next_inode(root, objectid); if (!inode) break; ino = btrfs_ino(BTRFS_I(inode)); if (ino > max_key->objectid) { iput(inode); break; } objectid = ino + 1; if (!S_ISREG(inode->i_mode)) continue; if (unlikely(min_key->objectid == ino)) { if (min_key->type > BTRFS_EXTENT_DATA_KEY) continue; if (min_key->type < BTRFS_EXTENT_DATA_KEY) start = 0; else { start = min_key->offset; WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize)); } } else { start = 0; } if (unlikely(max_key->objectid == ino)) { if (max_key->type < BTRFS_EXTENT_DATA_KEY) continue; if (max_key->type > BTRFS_EXTENT_DATA_KEY) { end = (u64)-1; } else { if (max_key->offset == 0) continue; end = max_key->offset; WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize)); end--; } } else { end = (u64)-1; } /* the lock_extent waits for read_folio to complete */ lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state); btrfs_drop_extent_map_range(BTRFS_I(inode), start, end, true); unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state); } return 0; } static int find_next_key(struct btrfs_path *path, int level, struct btrfs_key *key) { while (level < BTRFS_MAX_LEVEL) { if (!path->nodes[level]) break; if (path->slots[level] + 1 < btrfs_header_nritems(path->nodes[level])) { btrfs_node_key_to_cpu(path->nodes[level], key, path->slots[level] + 1); return 0; } level++; } return 1; } /* * Insert current subvolume into reloc_control::dirty_subvol_roots */ static int insert_dirty_subvol(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_root *root) { struct btrfs_root *reloc_root = root->reloc_root; struct btrfs_root_item *reloc_root_item; int ret; /* @root must be a subvolume tree root with a valid reloc tree */ ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); ASSERT(reloc_root); reloc_root_item = &reloc_root->root_item; memset(&reloc_root_item->drop_progress, 0, sizeof(reloc_root_item->drop_progress)); btrfs_set_root_drop_level(reloc_root_item, 0); btrfs_set_root_refs(reloc_root_item, 0); ret = btrfs_update_reloc_root(trans, root); if (ret) return ret; if (list_empty(&root->reloc_dirty_list)) { btrfs_grab_root(root); list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots); } return 0; } static int clean_dirty_subvols(struct reloc_control *rc) { struct btrfs_root *root; struct btrfs_root *next; int ret = 0; int ret2; list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots, reloc_dirty_list) { if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { /* Merged subvolume, cleanup its reloc root */ struct btrfs_root *reloc_root = root->reloc_root; list_del_init(&root->reloc_dirty_list); root->reloc_root = NULL; /* * Need barrier to ensure clear_bit() only happens after * root->reloc_root = NULL. Pairs with have_reloc_root. */ smp_wmb(); clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state); if (reloc_root) { /* * btrfs_drop_snapshot drops our ref we hold for * ->reloc_root. If it fails however we must * drop the ref ourselves. */ ret2 = btrfs_drop_snapshot(reloc_root, 0, 1); if (ret2 < 0) { btrfs_put_root(reloc_root); if (!ret) ret = ret2; } } btrfs_put_root(root); } else { /* Orphan reloc tree, just clean it up */ ret2 = btrfs_drop_snapshot(root, 0, 1); if (ret2 < 0) { btrfs_put_root(root); if (!ret) ret = ret2; } } } return ret; } /* * merge the relocated tree blocks in reloc tree with corresponding * fs tree. */ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, struct btrfs_root *root) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct btrfs_key key; struct btrfs_key next_key; struct btrfs_trans_handle *trans = NULL; struct btrfs_root *reloc_root; struct btrfs_root_item *root_item; struct btrfs_path *path; struct extent_buffer *leaf; int reserve_level; int level; int max_level; int replaced = 0; int ret = 0; u32 min_reserved; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = READA_FORWARD; reloc_root = root->reloc_root; root_item = &reloc_root->root_item; if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) { level = btrfs_root_level(root_item); atomic_inc(&reloc_root->node->refs); path->nodes[level] = reloc_root->node; path->slots[level] = 0; } else { btrfs_disk_key_to_cpu(&key, &root_item->drop_progress); level = btrfs_root_drop_level(root_item); BUG_ON(level == 0); path->lowest_level = level; ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0); path->lowest_level = 0; if (ret < 0) { btrfs_free_path(path); return ret; } btrfs_node_key_to_cpu(path->nodes[level], &next_key, path->slots[level]); WARN_ON(memcmp(&key, &next_key, sizeof(key))); btrfs_unlock_up_safe(path, 0); } /* * In merge_reloc_root(), we modify the upper level pointer to swap the * tree blocks between reloc tree and subvolume tree. Thus for tree * block COW, we COW at most from level 1 to root level for each tree. * * Thus the needed metadata size is at most root_level * nodesize, * and * 2 since we have two trees to COW. */ reserve_level = max_t(int, 1, btrfs_root_level(root_item)); min_reserved = fs_info->nodesize * reserve_level * 2; memset(&next_key, 0, sizeof(next_key)); while (1) { ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, min_reserved, BTRFS_RESERVE_FLUSH_LIMIT); if (ret) goto out; trans = btrfs_start_transaction(root, 0); if (IS_ERR(trans)) { ret = PTR_ERR(trans); trans = NULL; goto out; } /* * At this point we no longer have a reloc_control, so we can't * depend on btrfs_init_reloc_root to update our last_trans. * * But that's ok, we started the trans handle on our * corresponding fs_root, which means it's been added to the * dirty list. At commit time we'll still call * btrfs_update_reloc_root() and update our root item * appropriately. */ reloc_root->last_trans = trans->transid; trans->block_rsv = rc->block_rsv; replaced = 0; max_level = level; ret = walk_down_reloc_tree(reloc_root, path, &level); if (ret < 0) goto out; if (ret > 0) break; if (!find_next_key(path, level, &key) && btrfs_comp_cpu_keys(&next_key, &key) >= 0) { ret = 0; } else { ret = replace_path(trans, rc, root, reloc_root, path, &next_key, level, max_level); } if (ret < 0) goto out; if (ret > 0) { level = ret; btrfs_node_key_to_cpu(path->nodes[level], &key, path->slots[level]); replaced = 1; } ret = walk_up_reloc_tree(reloc_root, path, &level); if (ret > 0) break; BUG_ON(level == 0); /* * save the merging progress in the drop_progress. * this is OK since root refs == 1 in this case. */ btrfs_node_key(path->nodes[level], &root_item->drop_progress, path->slots[level]); btrfs_set_root_drop_level(root_item, level); btrfs_end_transaction_throttle(trans); trans = NULL; btrfs_btree_balance_dirty(fs_info); if (replaced && rc->stage == UPDATE_DATA_PTRS) invalidate_extent_cache(root, &key, &next_key); } /* * handle the case only one block in the fs tree need to be * relocated and the block is tree root. */ leaf = btrfs_lock_root_node(root); ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf, BTRFS_NESTING_COW); btrfs_tree_unlock(leaf); free_extent_buffer(leaf); out: btrfs_free_path(path); if (ret == 0) { ret = insert_dirty_subvol(trans, rc, root); if (ret) btrfs_abort_transaction(trans, ret); } if (trans) btrfs_end_transaction_throttle(trans); btrfs_btree_balance_dirty(fs_info); if (replaced && rc->stage == UPDATE_DATA_PTRS) invalidate_extent_cache(root, &key, &next_key); return ret; } static noinline_for_stack int prepare_to_merge(struct reloc_control *rc, int err) { struct btrfs_root *root = rc->extent_root; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_root *reloc_root; struct btrfs_trans_handle *trans; LIST_HEAD(reloc_roots); u64 num_bytes = 0; int ret; mutex_lock(&fs_info->reloc_mutex); rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2; rc->merging_rsv_size += rc->nodes_relocated * 2; mutex_unlock(&fs_info->reloc_mutex); again: if (!err) { num_bytes = rc->merging_rsv_size; ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes, BTRFS_RESERVE_FLUSH_ALL); if (ret) err = ret; } trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { if (!err) btrfs_block_rsv_release(fs_info, rc->block_rsv, num_bytes, NULL); return PTR_ERR(trans); } if (!err) { if (num_bytes != rc->merging_rsv_size) { btrfs_end_transaction(trans); btrfs_block_rsv_release(fs_info, rc->block_rsv, num_bytes, NULL); goto again; } } rc->merge_reloc_tree = true; while (!list_empty(&rc->reloc_roots)) { reloc_root = list_entry(rc->reloc_roots.next, struct btrfs_root, root_list); list_del_init(&reloc_root->root_list); root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false); if (IS_ERR(root)) { /* * Even if we have an error we need this reloc root * back on our list so we can clean up properly. */ list_add(&reloc_root->root_list, &reloc_roots); btrfs_abort_transaction(trans, (int)PTR_ERR(root)); if (!err) err = PTR_ERR(root); break; } if (unlikely(root->reloc_root != reloc_root)) { if (root->reloc_root) { btrfs_err(fs_info, "reloc tree mismatch, root %lld has reloc root key (%lld %u %llu) gen %llu, expect reloc root key (%lld %u %llu) gen %llu", root->root_key.objectid, root->reloc_root->root_key.objectid, root->reloc_root->root_key.type, root->reloc_root->root_key.offset, btrfs_root_generation( &root->reloc_root->root_item), reloc_root->root_key.objectid, reloc_root->root_key.type, reloc_root->root_key.offset, btrfs_root_generation( &reloc_root->root_item)); } else { btrfs_err(fs_info, "reloc tree mismatch, root %lld has no reloc root, expect reloc root key (%lld %u %llu) gen %llu", root->root_key.objectid, reloc_root->root_key.objectid, reloc_root->root_key.type, reloc_root->root_key.offset, btrfs_root_generation( &reloc_root->root_item)); } list_add(&reloc_root->root_list, &reloc_roots); btrfs_put_root(root); btrfs_abort_transaction(trans, -EUCLEAN); if (!err) err = -EUCLEAN; break; } /* * set reference count to 1, so btrfs_recover_relocation * knows it should resumes merging */ if (!err) btrfs_set_root_refs(&reloc_root->root_item, 1); ret = btrfs_update_reloc_root(trans, root); /* * Even if we have an error we need this reloc root back on our * list so we can clean up properly. */ list_add(&reloc_root->root_list, &reloc_roots); btrfs_put_root(root); if (ret) { btrfs_abort_transaction(trans, ret); if (!err) err = ret; break; } } list_splice(&reloc_roots, &rc->reloc_roots); if (!err) err = btrfs_commit_transaction(trans); else btrfs_end_transaction(trans); return err; } static noinline_for_stack void free_reloc_roots(struct list_head *list) { struct btrfs_root *reloc_root, *tmp; list_for_each_entry_safe(reloc_root, tmp, list, root_list) __del_reloc_root(reloc_root); } static noinline_for_stack void merge_reloc_roots(struct reloc_control *rc) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct btrfs_root *root; struct btrfs_root *reloc_root; LIST_HEAD(reloc_roots); int found = 0; int ret = 0; again: root = rc->extent_root; /* * this serializes us with btrfs_record_root_in_transaction, * we have to make sure nobody is in the middle of * adding their roots to the list while we are * doing this splice */ mutex_lock(&fs_info->reloc_mutex); list_splice_init(&rc->reloc_roots, &reloc_roots); mutex_unlock(&fs_info->reloc_mutex); while (!list_empty(&reloc_roots)) { found = 1; reloc_root = list_entry(reloc_roots.next, struct btrfs_root, root_list); root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false); if (btrfs_root_refs(&reloc_root->root_item) > 0) { if (WARN_ON(IS_ERR(root))) { /* * For recovery we read the fs roots on mount, * and if we didn't find the root then we marked * the reloc root as a garbage root. For normal * relocation obviously the root should exist in * memory. However there's no reason we can't * handle the error properly here just in case. */ ret = PTR_ERR(root); goto out; } if (WARN_ON(root->reloc_root != reloc_root)) { /* * This can happen if on-disk metadata has some * corruption, e.g. bad reloc tree key offset. */ ret = -EINVAL; goto out; } ret = merge_reloc_root(rc, root); btrfs_put_root(root); if (ret) { if (list_empty(&reloc_root->root_list)) list_add_tail(&reloc_root->root_list, &reloc_roots); goto out; } } else { if (!IS_ERR(root)) { if (root->reloc_root == reloc_root) { root->reloc_root = NULL; btrfs_put_root(reloc_root); } clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state); btrfs_put_root(root); } list_del_init(&reloc_root->root_list); /* Don't forget to queue this reloc root for cleanup */ list_add_tail(&reloc_root->reloc_dirty_list, &rc->dirty_subvol_roots); } } if (found) { found = 0; goto again; } out: if (ret) { btrfs_handle_fs_error(fs_info, ret, NULL); free_reloc_roots(&reloc_roots); /* new reloc root may be added */ mutex_lock(&fs_info->reloc_mutex); list_splice_init(&rc->reloc_roots, &reloc_roots); mutex_unlock(&fs_info->reloc_mutex); free_reloc_roots(&reloc_roots); } /* * We used to have * * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root)); * * here, but it's wrong. If we fail to start the transaction in * prepare_to_merge() we will have only 0 ref reloc roots, none of which * have actually been removed from the reloc_root_tree rb tree. This is * fine because we're bailing here, and we hold a reference on the root * for the list that holds it, so these roots will be cleaned up when we * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root * will be cleaned up on unmount. * * The remaining nodes will be cleaned up by free_reloc_control. */ } static void free_block_list(struct rb_root *blocks) { struct tree_block *block; struct rb_node *rb_node; while ((rb_node = rb_first(blocks))) { block = rb_entry(rb_node, struct tree_block, rb_node); rb_erase(rb_node, blocks); kfree(block); } } static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans, struct btrfs_root *reloc_root) { struct btrfs_fs_info *fs_info = reloc_root->fs_info; struct btrfs_root *root; int ret; if (reloc_root->last_trans == trans->transid) return 0; root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false); /* * This should succeed, since we can't have a reloc root without having * already looked up the actual root and created the reloc root for this * root. * * However if there's some sort of corruption where we have a ref to a * reloc root without a corresponding root this could return ENOENT. */ if (IS_ERR(root)) { ASSERT(0); return PTR_ERR(root); } if (root->reloc_root != reloc_root) { ASSERT(0); btrfs_err(fs_info, "root %llu has two reloc roots associated with it", reloc_root->root_key.offset); btrfs_put_root(root); return -EUCLEAN; } ret = btrfs_record_root_in_trans(trans, root); btrfs_put_root(root); return ret; } static noinline_for_stack struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_backref_node *node, struct btrfs_backref_edge *edges[]) { struct btrfs_backref_node *next; struct btrfs_root *root; int index = 0; int ret; next = node; while (1) { cond_resched(); next = walk_up_backref(next, edges, &index); root = next->root; /* * If there is no root, then our references for this block are * incomplete, as we should be able to walk all the way up to a * block that is owned by a root. * * This path is only for SHAREABLE roots, so if we come upon a * non-SHAREABLE root then we have backrefs that resolve * improperly. * * Both of these cases indicate file system corruption, or a bug * in the backref walking code. */ if (!root) { ASSERT(0); btrfs_err(trans->fs_info, "bytenr %llu doesn't have a backref path ending in a root", node->bytenr); return ERR_PTR(-EUCLEAN); } if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { ASSERT(0); btrfs_err(trans->fs_info, "bytenr %llu has multiple refs with one ending in a non-shareable root", node->bytenr); return ERR_PTR(-EUCLEAN); } if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { ret = record_reloc_root_in_trans(trans, root); if (ret) return ERR_PTR(ret); break; } ret = btrfs_record_root_in_trans(trans, root); if (ret) return ERR_PTR(ret); root = root->reloc_root; /* * We could have raced with another thread which failed, so * root->reloc_root may not be set, return ENOENT in this case. */ if (!root) return ERR_PTR(-ENOENT); if (next->new_bytenr != root->node->start) { /* * We just created the reloc root, so we shouldn't have * ->new_bytenr set and this shouldn't be in the changed * list. If it is then we have multiple roots pointing * at the same bytenr which indicates corruption, or * we've made a mistake in the backref walking code. */ ASSERT(next->new_bytenr == 0); ASSERT(list_empty(&next->list)); if (next->new_bytenr || !list_empty(&next->list)) { btrfs_err(trans->fs_info, "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu", node->bytenr, next->bytenr); return ERR_PTR(-EUCLEAN); } next->new_bytenr = root->node->start; btrfs_put_root(next->root); next->root = btrfs_grab_root(root); ASSERT(next->root); list_add_tail(&next->list, &rc->backref_cache.changed); mark_block_processed(rc, next); break; } WARN_ON(1); root = NULL; next = walk_down_backref(edges, &index); if (!next || next->level <= node->level) break; } if (!root) { /* * This can happen if there's fs corruption or if there's a bug * in the backref lookup code. */ ASSERT(0); return ERR_PTR(-ENOENT); } next = node; /* setup backref node path for btrfs_reloc_cow_block */ while (1) { rc->backref_cache.path[next->level] = next; if (--index < 0) break; next = edges[index]->node[UPPER]; } return root; } /* * Select a tree root for relocation. * * Return NULL if the block is not shareable. We should use do_relocation() in * this case. * * Return a tree root pointer if the block is shareable. * Return -ENOENT if the block is root of reloc tree. */ static noinline_for_stack struct btrfs_root *select_one_root(struct btrfs_backref_node *node) { struct btrfs_backref_node *next; struct btrfs_root *root; struct btrfs_root *fs_root = NULL; struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; int index = 0; next = node; while (1) { cond_resched(); next = walk_up_backref(next, edges, &index); root = next->root; /* * This can occur if we have incomplete extent refs leading all * the way up a particular path, in this case return -EUCLEAN. */ if (!root) return ERR_PTR(-EUCLEAN); /* No other choice for non-shareable tree */ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) return root; if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) fs_root = root; if (next != node) return NULL; next = walk_down_backref(edges, &index); if (!next || next->level <= node->level) break; } if (!fs_root) return ERR_PTR(-ENOENT); return fs_root; } static noinline_for_stack u64 calcu_metadata_size(struct reloc_control *rc, struct btrfs_backref_node *node, int reserve) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct btrfs_backref_node *next = node; struct btrfs_backref_edge *edge; struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; u64 num_bytes = 0; int index = 0; BUG_ON(reserve && node->processed); while (next) { cond_resched(); while (1) { if (next->processed && (reserve || next != node)) break; num_bytes += fs_info->nodesize; if (list_empty(&next->upper)) break; edge = list_entry(next->upper.next, struct btrfs_backref_edge, list[LOWER]); edges[index++] = edge; next = edge->node[UPPER]; } next = walk_down_backref(edges, &index); } return num_bytes; } static int reserve_metadata_space(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_backref_node *node) { struct btrfs_root *root = rc->extent_root; struct btrfs_fs_info *fs_info = root->fs_info; u64 num_bytes; int ret; u64 tmp; num_bytes = calcu_metadata_size(rc, node, 1) * 2; trans->block_rsv = rc->block_rsv; rc->reserved_bytes += num_bytes; /* * We are under a transaction here so we can only do limited flushing. * If we get an enospc just kick back -EAGAIN so we know to drop the * transaction and try to refill when we can flush all the things. */ ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes, BTRFS_RESERVE_FLUSH_LIMIT); if (ret) { tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES; while (tmp <= rc->reserved_bytes) tmp <<= 1; /* * only one thread can access block_rsv at this point, * so we don't need hold lock to protect block_rsv. * we expand more reservation size here to allow enough * space for relocation and we will return earlier in * enospc case. */ rc->block_rsv->size = tmp + fs_info->nodesize * RELOCATION_RESERVED_NODES; return -EAGAIN; } return 0; } /* * relocate a block tree, and then update pointers in upper level * blocks that reference the block to point to the new location. * * if called by link_to_upper, the block has already been relocated. * in that case this function just updates pointers. */ static int do_relocation(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_backref_node *node, struct btrfs_key *key, struct btrfs_path *path, int lowest) { struct btrfs_backref_node *upper; struct btrfs_backref_edge *edge; struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; struct btrfs_root *root; struct extent_buffer *eb; u32 blocksize; u64 bytenr; int slot; int ret = 0; /* * If we are lowest then this is the first time we're processing this * block, and thus shouldn't have an eb associated with it yet. */ ASSERT(!lowest || !node->eb); path->lowest_level = node->level + 1; rc->backref_cache.path[node->level] = node; list_for_each_entry(edge, &node->upper, list[LOWER]) { struct btrfs_ref ref = { 0 }; cond_resched(); upper = edge->node[UPPER]; root = select_reloc_root(trans, rc, upper, edges); if (IS_ERR(root)) { ret = PTR_ERR(root); goto next; } if (upper->eb && !upper->locked) { if (!lowest) { ret = btrfs_bin_search(upper->eb, 0, key, &slot); if (ret < 0) goto next; BUG_ON(ret); bytenr = btrfs_node_blockptr(upper->eb, slot); if (node->eb->start == bytenr) goto next; } btrfs_backref_drop_node_buffer(upper); } if (!upper->eb) { ret = btrfs_search_slot(trans, root, key, path, 0, 1); if (ret) { if (ret > 0) ret = -ENOENT; btrfs_release_path(path); break; } if (!upper->eb) { upper->eb = path->nodes[upper->level]; path->nodes[upper->level] = NULL; } else { BUG_ON(upper->eb != path->nodes[upper->level]); } upper->locked = 1; path->locks[upper->level] = 0; slot = path->slots[upper->level]; btrfs_release_path(path); } else { ret = btrfs_bin_search(upper->eb, 0, key, &slot); if (ret < 0) goto next; BUG_ON(ret); } bytenr = btrfs_node_blockptr(upper->eb, slot); if (lowest) { if (bytenr != node->bytenr) { btrfs_err(root->fs_info, "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu", bytenr, node->bytenr, slot, upper->eb->start); ret = -EIO; goto next; } } else { if (node->eb->start == bytenr) goto next; } blocksize = root->fs_info->nodesize; eb = btrfs_read_node_slot(upper->eb, slot); if (IS_ERR(eb)) { ret = PTR_ERR(eb); goto next; } btrfs_tree_lock(eb); if (!node->eb) { ret = btrfs_cow_block(trans, root, eb, upper->eb, slot, &eb, BTRFS_NESTING_COW); btrfs_tree_unlock(eb); free_extent_buffer(eb); if (ret < 0) goto next; /* * We've just COWed this block, it should have updated * the correct backref node entry. */ ASSERT(node->eb == eb); } else { btrfs_set_node_blockptr(upper->eb, slot, node->eb->start); btrfs_set_node_ptr_generation(upper->eb, slot, trans->transid); btrfs_mark_buffer_dirty(trans, upper->eb); btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, node->eb->start, blocksize, upper->eb->start, btrfs_header_owner(upper->eb)); btrfs_init_tree_ref(&ref, node->level, btrfs_header_owner(upper->eb), root->root_key.objectid, false); ret = btrfs_inc_extent_ref(trans, &ref); if (!ret) ret = btrfs_drop_subtree(trans, root, eb, upper->eb); if (ret) btrfs_abort_transaction(trans, ret); } next: if (!upper->pending) btrfs_backref_drop_node_buffer(upper); else btrfs_backref_unlock_node_buffer(upper); if (ret) break; } if (!ret && node->pending) { btrfs_backref_drop_node_buffer(node); list_move_tail(&node->list, &rc->backref_cache.changed); node->pending = 0; } path->lowest_level = 0; /* * We should have allocated all of our space in the block rsv and thus * shouldn't ENOSPC. */ ASSERT(ret != -ENOSPC); return ret; } static int link_to_upper(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_backref_node *node, struct btrfs_path *path) { struct btrfs_key key; btrfs_node_key_to_cpu(node->eb, &key, 0); return do_relocation(trans, rc, node, &key, path, 0); } static int finish_pending_nodes(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_path *path, int err) { LIST_HEAD(list); struct btrfs_backref_cache *cache = &rc->backref_cache; struct btrfs_backref_node *node; int level; int ret; for (level = 0; level < BTRFS_MAX_LEVEL; level++) { while (!list_empty(&cache->pending[level])) { node = list_entry(cache->pending[level].next, struct btrfs_backref_node, list); list_move_tail(&node->list, &list); BUG_ON(!node->pending); if (!err) { ret = link_to_upper(trans, rc, node, path); if (ret < 0) err = ret; } } list_splice_init(&list, &cache->pending[level]); } return err; } /* * mark a block and all blocks directly/indirectly reference the block * as processed. */ static void update_processed_blocks(struct reloc_control *rc, struct btrfs_backref_node *node) { struct btrfs_backref_node *next = node; struct btrfs_backref_edge *edge; struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1]; int index = 0; while (next) { cond_resched(); while (1) { if (next->processed) break; mark_block_processed(rc, next); if (list_empty(&next->upper)) break; edge = list_entry(next->upper.next, struct btrfs_backref_edge, list[LOWER]); edges[index++] = edge; next = edge->node[UPPER]; } next = walk_down_backref(edges, &index); } } static int tree_block_processed(u64 bytenr, struct reloc_control *rc) { u32 blocksize = rc->extent_root->fs_info->nodesize; if (test_range_bit(&rc->processed_blocks, bytenr, bytenr + blocksize - 1, EXTENT_DIRTY, NULL)) return 1; return 0; } static int get_tree_block_key(struct btrfs_fs_info *fs_info, struct tree_block *block) { struct btrfs_tree_parent_check check = { .level = block->level, .owner_root = block->owner, .transid = block->key.offset }; struct extent_buffer *eb; eb = read_tree_block(fs_info, block->bytenr, &check); if (IS_ERR(eb)) return PTR_ERR(eb); if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); return -EIO; } if (block->level == 0) btrfs_item_key_to_cpu(eb, &block->key, 0); else btrfs_node_key_to_cpu(eb, &block->key, 0); free_extent_buffer(eb); block->key_ready = true; return 0; } /* * helper function to relocate a tree block */ static int relocate_tree_block(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct btrfs_backref_node *node, struct btrfs_key *key, struct btrfs_path *path) { struct btrfs_root *root; int ret = 0; if (!node) return 0; /* * If we fail here we want to drop our backref_node because we are going * to start over and regenerate the tree for it. */ ret = reserve_metadata_space(trans, rc, node); if (ret) goto out; BUG_ON(node->processed); root = select_one_root(node); if (IS_ERR(root)) { ret = PTR_ERR(root); /* See explanation in select_one_root for the -EUCLEAN case. */ ASSERT(ret == -ENOENT); if (ret == -ENOENT) { ret = 0; update_processed_blocks(rc, node); } goto out; } if (root) { if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { /* * This block was the root block of a root, and this is * the first time we're processing the block and thus it * should not have had the ->new_bytenr modified and * should have not been included on the changed list. * * However in the case of corruption we could have * multiple refs pointing to the same block improperly, * and thus we would trip over these checks. ASSERT() * for the developer case, because it could indicate a * bug in the backref code, however error out for a * normal user in the case of corruption. */ ASSERT(node->new_bytenr == 0); ASSERT(list_empty(&node->list)); if (node->new_bytenr || !list_empty(&node->list)) { btrfs_err(root->fs_info, "bytenr %llu has improper references to it", node->bytenr); ret = -EUCLEAN; goto out; } ret = btrfs_record_root_in_trans(trans, root); if (ret) goto out; /* * Another thread could have failed, need to check if we * have reloc_root actually set. */ if (!root->reloc_root) { ret = -ENOENT; goto out; } root = root->reloc_root; node->new_bytenr = root->node->start; btrfs_put_root(node->root); node->root = btrfs_grab_root(root); ASSERT(node->root); list_add_tail(&node->list, &rc->backref_cache.changed); } else { path->lowest_level = node->level; if (root == root->fs_info->chunk_root) btrfs_reserve_chunk_metadata(trans, false); ret = btrfs_search_slot(trans, root, key, path, 0, 1); btrfs_release_path(path); if (root == root->fs_info->chunk_root) btrfs_trans_release_chunk_metadata(trans); if (ret > 0) ret = 0; } if (!ret) update_processed_blocks(rc, node); } else { ret = do_relocation(trans, rc, node, key, path, 1); } out: if (ret || node->level == 0 || node->cowonly) btrfs_backref_cleanup_node(&rc->backref_cache, node); return ret; } /* * relocate a list of blocks */ static noinline_for_stack int relocate_tree_blocks(struct btrfs_trans_handle *trans, struct reloc_control *rc, struct rb_root *blocks) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct btrfs_backref_node *node; struct btrfs_path *path; struct tree_block *block; struct tree_block *next; int ret; int err = 0; path = btrfs_alloc_path(); if (!path) { err = -ENOMEM; goto out_free_blocks; } /* Kick in readahead for tree blocks with missing keys */ rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) { if (!block->key_ready) btrfs_readahead_tree_block(fs_info, block->bytenr, block->owner, 0, block->level); } /* Get first keys */ rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) { if (!block->key_ready) { err = get_tree_block_key(fs_info, block); if (err) goto out_free_path; } } /* Do tree relocation */ rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) { node = build_backref_tree(trans, rc, &block->key, block->level, block->bytenr); if (IS_ERR(node)) { err = PTR_ERR(node); goto out; } ret = relocate_tree_block(trans, rc, node, &block->key, path); if (ret < 0) { err = ret; break; } } out: err = finish_pending_nodes(trans, rc, path, err); out_free_path: btrfs_free_path(path); out_free_blocks: free_block_list(blocks); return err; } static noinline_for_stack int prealloc_file_extent_cluster( struct btrfs_inode *inode, const struct file_extent_cluster *cluster) { u64 alloc_hint = 0; u64 start; u64 end; u64 offset = inode->index_cnt; u64 num_bytes; int nr; int ret = 0; u64 i_size = i_size_read(&inode->vfs_inode); u64 prealloc_start = cluster->start - offset; u64 prealloc_end = cluster->end - offset; u64 cur_offset = prealloc_start; /* * For subpage case, previous i_size may not be aligned to PAGE_SIZE. * This means the range [i_size, PAGE_END + 1) is filled with zeros by * btrfs_do_readpage() call of previously relocated file cluster. * * If the current cluster starts in the above range, btrfs_do_readpage() * will skip the read, and relocate_one_page() will later writeback * the padding zeros as new data, causing data corruption. * * Here we have to manually invalidate the range (i_size, PAGE_END + 1). */ if (!PAGE_ALIGNED(i_size)) { struct address_space *mapping = inode->vfs_inode.i_mapping; struct btrfs_fs_info *fs_info = inode->root->fs_info; const u32 sectorsize = fs_info->sectorsize; struct page *page; ASSERT(sectorsize < PAGE_SIZE); ASSERT(IS_ALIGNED(i_size, sectorsize)); /* * Subpage can't handle page with DIRTY but without UPTODATE * bit as it can lead to the following deadlock: * * btrfs_read_folio() * | Page already *locked* * |- btrfs_lock_and_flush_ordered_range() * |- btrfs_start_ordered_extent() * |- extent_write_cache_pages() * |- lock_page() * We try to lock the page we already hold. * * Here we just writeback the whole data reloc inode, so that * we will be ensured to have no dirty range in the page, and * are safe to clear the uptodate bits. * * This shouldn't cause too much overhead, as we need to write * the data back anyway. */ ret = filemap_write_and_wait(mapping); if (ret < 0) return ret; clear_extent_bits(&inode->io_tree, i_size, round_up(i_size, PAGE_SIZE) - 1, EXTENT_UPTODATE); page = find_lock_page(mapping, i_size >> PAGE_SHIFT); /* * If page is freed we don't need to do anything then, as we * will re-read the whole page anyway. */ if (page) { btrfs_subpage_clear_uptodate(fs_info, page_folio(page), i_size, round_up(i_size, PAGE_SIZE) - i_size); unlock_page(page); put_page(page); } } BUG_ON(cluster->start != cluster->boundary[0]); ret = btrfs_alloc_data_chunk_ondemand(inode, prealloc_end + 1 - prealloc_start); if (ret) return ret; btrfs_inode_lock(inode, 0); for (nr = 0; nr < cluster->nr; nr++) { struct extent_state *cached_state = NULL; start = cluster->boundary[nr] - offset; if (nr + 1 < cluster->nr) end = cluster->boundary[nr + 1] - 1 - offset; else end = cluster->end - offset; lock_extent(&inode->io_tree, start, end, &cached_state); num_bytes = end + 1 - start; ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start, num_bytes, num_bytes, end + 1, &alloc_hint); cur_offset = end + 1; unlock_extent(&inode->io_tree, start, end, &cached_state); if (ret) break; } btrfs_inode_unlock(inode, 0); if (cur_offset < prealloc_end) btrfs_free_reserved_data_space_noquota(inode->root->fs_info, prealloc_end + 1 - cur_offset); return ret; } static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inode, u64 start, u64 end, u64 block_start) { struct extent_map *em; struct extent_state *cached_state = NULL; int ret = 0; em = alloc_extent_map(); if (!em) return -ENOMEM; em->start = start; em->len = end + 1 - start; em->block_len = em->len; em->block_start = block_start; em->flags |= EXTENT_FLAG_PINNED; lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state); ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, false); unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state); free_extent_map(em); return ret; } /* * Allow error injection to test balance/relocation cancellation */ noinline int btrfs_should_cancel_balance(const struct btrfs_fs_info *fs_info) { return atomic_read(&fs_info->balance_cancel_req) || atomic_read(&fs_info->reloc_cancel_req) || fatal_signal_pending(current); } ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE); static u64 get_cluster_boundary_end(const struct file_extent_cluster *cluster, int cluster_nr) { /* Last extent, use cluster end directly */ if (cluster_nr >= cluster->nr - 1) return cluster->end; /* Use next boundary start*/ return cluster->boundary[cluster_nr + 1] - 1; } static int relocate_one_page(struct inode *inode, struct file_ra_state *ra, const struct file_extent_cluster *cluster, int *cluster_nr, unsigned long page_index) { struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); u64 offset = BTRFS_I(inode)->index_cnt; const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT; gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); struct page *page; u64 page_start; u64 page_end; u64 cur; int ret; ASSERT(page_index <= last_index); page = find_lock_page(inode->i_mapping, page_index); if (!page) { page_cache_sync_readahead(inode->i_mapping, ra, NULL, page_index, last_index + 1 - page_index); page = find_or_create_page(inode->i_mapping, page_index, mask); if (!page) return -ENOMEM; } if (PageReadahead(page)) page_cache_async_readahead(inode->i_mapping, ra, NULL, page_folio(page), page_index, last_index + 1 - page_index); if (!PageUptodate(page)) { btrfs_read_folio(NULL, page_folio(page)); lock_page(page); if (!PageUptodate(page)) { ret = -EIO; goto release_page; } } /* * We could have lost page private when we dropped the lock to read the * page above, make sure we set_page_extent_mapped here so we have any * of the subpage blocksize stuff we need in place. */ ret = set_page_extent_mapped(page); if (ret < 0) goto release_page; page_start = page_offset(page); page_end = page_start + PAGE_SIZE - 1; /* * Start from the cluster, as for subpage case, the cluster can start * inside the page. */ cur = max(page_start, cluster->boundary[*cluster_nr] - offset); while (cur <= page_end) { struct extent_state *cached_state = NULL; u64 extent_start = cluster->boundary[*cluster_nr] - offset; u64 extent_end = get_cluster_boundary_end(cluster, *cluster_nr) - offset; u64 clamped_start = max(page_start, extent_start); u64 clamped_end = min(page_end, extent_end); u32 clamped_len = clamped_end + 1 - clamped_start; /* Reserve metadata for this range */ ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), clamped_len, clamped_len, false); if (ret) goto release_page; /* Mark the range delalloc and dirty for later writeback */ lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end, &cached_state); ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start, clamped_end, 0, &cached_state); if (ret) { clear_extent_bit(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end, EXTENT_LOCKED | EXTENT_BOUNDARY, &cached_state); btrfs_delalloc_release_metadata(BTRFS_I(inode), clamped_len, true); btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len); goto release_page; } btrfs_folio_set_dirty(fs_info, page_folio(page), clamped_start, clamped_len); /* * Set the boundary if it's inside the page. * Data relocation requires the destination extents to have the * same size as the source. * EXTENT_BOUNDARY bit prevents current extent from being merged * with previous extent. */ if (in_range(cluster->boundary[*cluster_nr] - offset, page_start, PAGE_SIZE)) { u64 boundary_start = cluster->boundary[*cluster_nr] - offset; u64 boundary_end = boundary_start + fs_info->sectorsize - 1; set_extent_bit(&BTRFS_I(inode)->io_tree, boundary_start, boundary_end, EXTENT_BOUNDARY, NULL); } unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end, &cached_state); btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len); cur += clamped_len; /* Crossed extent end, go to next extent */ if (cur >= extent_end) { (*cluster_nr)++; /* Just finished the last extent of the cluster, exit. */ if (*cluster_nr >= cluster->nr) break; } } unlock_page(page); put_page(page); balance_dirty_pages_ratelimited(inode->i_mapping); btrfs_throttle(fs_info); if (btrfs_should_cancel_balance(fs_info)) ret = -ECANCELED; return ret; release_page: unlock_page(page); put_page(page); return ret; } static int relocate_file_extent_cluster(struct inode *inode, const struct file_extent_cluster *cluster) { u64 offset = BTRFS_I(inode)->index_cnt; unsigned long index; unsigned long last_index; struct file_ra_state *ra; int cluster_nr = 0; int ret = 0; if (!cluster->nr) return 0; ra = kzalloc(sizeof(*ra), GFP_NOFS); if (!ra) return -ENOMEM; ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster); if (ret) goto out; file_ra_state_init(ra, inode->i_mapping); ret = setup_relocation_extent_mapping(inode, cluster->start - offset, cluster->end - offset, cluster->start); if (ret) goto out; last_index = (cluster->end - offset) >> PAGE_SHIFT; for (index = (cluster->start - offset) >> PAGE_SHIFT; index <= last_index && !ret; index++) ret = relocate_one_page(inode, ra, cluster, &cluster_nr, index); if (ret == 0) WARN_ON(cluster_nr != cluster->nr); out: kfree(ra); return ret; } static noinline_for_stack int relocate_data_extent(struct inode *inode, const struct btrfs_key *extent_key, struct file_extent_cluster *cluster) { int ret; struct btrfs_root *root = BTRFS_I(inode)->root; if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) { ret = relocate_file_extent_cluster(inode, cluster); if (ret) return ret; cluster->nr = 0; } /* * Under simple quotas, we set root->relocation_src_root when we find * the extent. If adjacent extents have different owners, we can't merge * them while relocating. Handle this by storing the owning root that * started a cluster and if we see an extent from a different root break * cluster formation (just like the above case of non-adjacent extents). * * Without simple quotas, relocation_src_root is always 0, so we should * never see a mismatch, and it should have no effect on relocation * clusters. */ if (cluster->nr > 0 && cluster->owning_root != root->relocation_src_root) { u64 tmp = root->relocation_src_root; /* * root->relocation_src_root is the state that actually affects * the preallocation we do here, so set it to the root owning * the cluster we need to relocate. */ root->relocation_src_root = cluster->owning_root; ret = relocate_file_extent_cluster(inode, cluster); if (ret) return ret; cluster->nr = 0; /* And reset it back for the current extent's owning root. */ root->relocation_src_root = tmp; } if (!cluster->nr) { cluster->start = extent_key->objectid; cluster->owning_root = root->relocation_src_root; } else BUG_ON(cluster->nr >= MAX_EXTENTS); cluster->end = extent_key->objectid + extent_key->offset - 1; cluster->boundary[cluster->nr] = extent_key->objectid; cluster->nr++; if (cluster->nr >= MAX_EXTENTS) { ret = relocate_file_extent_cluster(inode, cluster); if (ret) return ret; cluster->nr = 0; } return 0; } /* * helper to add a tree block to the list. * the major work is getting the generation and level of the block */ static int add_tree_block(struct reloc_control *rc, const struct btrfs_key *extent_key, struct btrfs_path *path, struct rb_root *blocks) { struct extent_buffer *eb; struct btrfs_extent_item *ei; struct btrfs_tree_block_info *bi; struct tree_block *block; struct rb_node *rb_node; u32 item_size; int level = -1; u64 generation; u64 owner = 0; eb = path->nodes[0]; item_size = btrfs_item_size(eb, path->slots[0]); if (extent_key->type == BTRFS_METADATA_ITEM_KEY || item_size >= sizeof(*ei) + sizeof(*bi)) { unsigned long ptr = 0, end; ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); end = (unsigned long)ei + item_size; if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) { bi = (struct btrfs_tree_block_info *)(ei + 1); level = btrfs_tree_block_level(eb, bi); ptr = (unsigned long)(bi + 1); } else { level = (int)extent_key->offset; ptr = (unsigned long)(ei + 1); } generation = btrfs_extent_generation(eb, ei); /* * We're reading random blocks without knowing their owner ahead * of time. This is ok most of the time, as all reloc roots and * fs roots have the same lock type. However normal trees do * not, and the only way to know ahead of time is to read the * inline ref offset. We know it's an fs root if * * 1. There's more than one ref. * 2. There's a SHARED_DATA_REF_KEY set. * 3. FULL_BACKREF is set on the flags. * * Otherwise it's safe to assume that the ref offset == the * owner of this block, so we can use that when calling * read_tree_block. */ if (btrfs_extent_refs(eb, ei) == 1 && !(btrfs_extent_flags(eb, ei) & BTRFS_BLOCK_FLAG_FULL_BACKREF) && ptr < end) { struct btrfs_extent_inline_ref *iref; int type; iref = (struct btrfs_extent_inline_ref *)ptr; type = btrfs_get_extent_inline_ref_type(eb, iref, BTRFS_REF_TYPE_BLOCK); if (type == BTRFS_REF_TYPE_INVALID) return -EINVAL; if (type == BTRFS_TREE_BLOCK_REF_KEY) owner = btrfs_extent_inline_ref_offset(eb, iref); } } else { btrfs_print_leaf(eb); btrfs_err(rc->block_group->fs_info, "unrecognized tree backref at tree block %llu slot %u", eb->start, path->slots[0]); btrfs_release_path(path); return -EUCLEAN; } btrfs_release_path(path); BUG_ON(level == -1); block = kmalloc(sizeof(*block), GFP_NOFS); if (!block) return -ENOMEM; block->bytenr = extent_key->objectid; block->key.objectid = rc->extent_root->fs_info->nodesize; block->key.offset = generation; block->level = level; block->key_ready = false; block->owner = owner; rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node); if (rb_node) btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr, -EEXIST); return 0; } /* * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY */ static int __add_tree_block(struct reloc_control *rc, u64 bytenr, u32 blocksize, struct rb_root *blocks) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct btrfs_path *path; struct btrfs_key key; int ret; bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA); if (tree_block_processed(bytenr, rc)) return 0; if (rb_simple_search(blocks, bytenr)) return 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; again: key.objectid = bytenr; if (skinny) { key.type = BTRFS_METADATA_ITEM_KEY; key.offset = (u64)-1; } else { key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = blocksize; } path->search_commit_root = 1; path->skip_locking = 1; ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0); if (ret < 0) goto out; if (ret > 0 && skinny) { if (path->slots[0]) { path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid == bytenr && (key.type == BTRFS_METADATA_ITEM_KEY || (key.type == BTRFS_EXTENT_ITEM_KEY && key.offset == blocksize))) ret = 0; } if (ret) { skinny = false; btrfs_release_path(path); goto again; } } if (ret) { ASSERT(ret == 1); btrfs_print_leaf(path->nodes[0]); btrfs_err(fs_info, "tree block extent item (%llu) is not found in extent tree", bytenr); WARN_ON(1); ret = -EINVAL; goto out; } ret = add_tree_block(rc, &key, path, blocks); out: btrfs_free_path(path); return ret; } static int delete_block_group_cache(struct btrfs_fs_info *fs_info, struct btrfs_block_group *block_group, struct inode *inode, u64 ino) { struct btrfs_root *root = fs_info->tree_root; struct btrfs_trans_handle *trans; int ret = 0; if (inode) goto truncate; inode = btrfs_iget(fs_info->sb, ino, root); if (IS_ERR(inode)) return -ENOENT; truncate: ret = btrfs_check_trunc_cache_free_space(fs_info, &fs_info->global_block_rsv); if (ret) goto out; trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); goto out; } ret = btrfs_truncate_free_space_cache(trans, block_group, inode); btrfs_end_transaction(trans); btrfs_btree_balance_dirty(fs_info); out: iput(inode); return ret; } /* * Locate the free space cache EXTENT_DATA in root tree leaf and delete the * cache inode, to avoid free space cache data extent blocking data relocation. */ static int delete_v1_space_cache(struct extent_buffer *leaf, struct btrfs_block_group *block_group, u64 data_bytenr) { u64 space_cache_ino; struct btrfs_file_extent_item *ei; struct btrfs_key key; bool found = false; int i; int ret; if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID) return 0; for (i = 0; i < btrfs_header_nritems(leaf); i++) { u8 type; btrfs_item_key_to_cpu(leaf, &key, i); if (key.type != BTRFS_EXTENT_DATA_KEY) continue; ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item); type = btrfs_file_extent_type(leaf, ei); if ((type == BTRFS_FILE_EXTENT_REG || type == BTRFS_FILE_EXTENT_PREALLOC) && btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) { found = true; space_cache_ino = key.objectid; break; } } if (!found) return -ENOENT; ret = delete_block_group_cache(leaf->fs_info, block_group, NULL, space_cache_ino); return ret; } /* * helper to find all tree blocks that reference a given data extent */ static noinline_for_stack int add_data_references(struct reloc_control *rc, const struct btrfs_key *extent_key, struct btrfs_path *path, struct rb_root *blocks) { struct btrfs_backref_walk_ctx ctx = { 0 }; struct ulist_iterator leaf_uiter; struct ulist_node *ref_node = NULL; const u32 blocksize = rc->extent_root->fs_info->nodesize; int ret = 0; btrfs_release_path(path); ctx.bytenr = extent_key->objectid; ctx.skip_inode_ref_list = true; ctx.fs_info = rc->extent_root->fs_info; ret = btrfs_find_all_leafs(&ctx); if (ret < 0) return ret; ULIST_ITER_INIT(&leaf_uiter); while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) { struct btrfs_tree_parent_check check = { 0 }; struct extent_buffer *eb; eb = read_tree_block(ctx.fs_info, ref_node->val, &check); if (IS_ERR(eb)) { ret = PTR_ERR(eb); break; } ret = delete_v1_space_cache(eb, rc->block_group, extent_key->objectid); free_extent_buffer(eb); if (ret < 0) break; ret = __add_tree_block(rc, ref_node->val, blocksize, blocks); if (ret < 0) break; } if (ret < 0) free_block_list(blocks); ulist_free(ctx.refs); return ret; } /* * helper to find next unprocessed extent */ static noinline_for_stack int find_next_extent(struct reloc_control *rc, struct btrfs_path *path, struct btrfs_key *extent_key) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct btrfs_key key; struct extent_buffer *leaf; u64 start, end, last; int ret; last = rc->block_group->start + rc->block_group->length; while (1) { bool block_found; cond_resched(); if (rc->search_start >= last) { ret = 1; break; } key.objectid = rc->search_start; key.type = BTRFS_EXTENT_ITEM_KEY; key.offset = 0; path->search_commit_root = 1; path->skip_locking = 1; ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0); if (ret < 0) break; next: leaf = path->nodes[0]; if (path->slots[0] >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(rc->extent_root, path); if (ret != 0) break; leaf = path->nodes[0]; } btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (key.objectid >= last) { ret = 1; break; } if (key.type != BTRFS_EXTENT_ITEM_KEY && key.type != BTRFS_METADATA_ITEM_KEY) { path->slots[0]++; goto next; } if (key.type == BTRFS_EXTENT_ITEM_KEY && key.objectid + key.offset <= rc->search_start) { path->slots[0]++; goto next; } if (key.type == BTRFS_METADATA_ITEM_KEY && key.objectid + fs_info->nodesize <= rc->search_start) { path->slots[0]++; goto next; } block_found = find_first_extent_bit(&rc->processed_blocks, key.objectid, &start, &end, EXTENT_DIRTY, NULL); if (block_found && start <= key.objectid) { btrfs_release_path(path); rc->search_start = end + 1; } else { if (key.type == BTRFS_EXTENT_ITEM_KEY) rc->search_start = key.objectid + key.offset; else rc->search_start = key.objectid + fs_info->nodesize; memcpy(extent_key, &key, sizeof(key)); return 0; } } btrfs_release_path(path); return ret; } static void set_reloc_control(struct reloc_control *rc) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; mutex_lock(&fs_info->reloc_mutex); fs_info->reloc_ctl = rc; mutex_unlock(&fs_info->reloc_mutex); } static void unset_reloc_control(struct reloc_control *rc) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; mutex_lock(&fs_info->reloc_mutex); fs_info->reloc_ctl = NULL; mutex_unlock(&fs_info->reloc_mutex); } static noinline_for_stack int prepare_to_relocate(struct reloc_control *rc) { struct btrfs_trans_handle *trans; int ret; rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info, BTRFS_BLOCK_RSV_TEMP); if (!rc->block_rsv) return -ENOMEM; memset(&rc->cluster, 0, sizeof(rc->cluster)); rc->search_start = rc->block_group->start; rc->extents_found = 0; rc->nodes_relocated = 0; rc->merging_rsv_size = 0; rc->reserved_bytes = 0; rc->block_rsv->size = rc->extent_root->fs_info->nodesize * RELOCATION_RESERVED_NODES; ret = btrfs_block_rsv_refill(rc->extent_root->fs_info, rc->block_rsv, rc->block_rsv->size, BTRFS_RESERVE_FLUSH_ALL); if (ret) return ret; rc->create_reloc_tree = true; set_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { unset_reloc_control(rc); /* * extent tree is not a ref_cow tree and has no reloc_root to * cleanup. And callers are responsible to free the above * block rsv. */ return PTR_ERR(trans); } ret = btrfs_commit_transaction(trans); if (ret) unset_reloc_control(rc); return ret; } static noinline_for_stack int relocate_block_group(struct reloc_control *rc) { struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; struct rb_root blocks = RB_ROOT; struct btrfs_key key; struct btrfs_trans_handle *trans = NULL; struct btrfs_path *path; struct btrfs_extent_item *ei; u64 flags; int ret; int err = 0; int progress = 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = READA_FORWARD; ret = prepare_to_relocate(rc); if (ret) { err = ret; goto out_free; } while (1) { rc->reserved_bytes = 0; ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, rc->block_rsv->size, BTRFS_RESERVE_FLUSH_ALL); if (ret) { err = ret; break; } progress++; trans = btrfs_start_transaction(rc->extent_root, 0); if (IS_ERR(trans)) { err = PTR_ERR(trans); trans = NULL; break; } restart: if (update_backref_cache(trans, &rc->backref_cache)) { btrfs_end_transaction(trans); trans = NULL; continue; } ret = find_next_extent(rc, path, &key); if (ret < 0) err = ret; if (ret != 0) break; rc->extents_found++; ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_extent_item); flags = btrfs_extent_flags(path->nodes[0], ei); /* * If we are relocating a simple quota owned extent item, we * need to note the owner on the reloc data root so that when * we allocate the replacement item, we can attribute it to the * correct eventual owner (rather than the reloc data root). */ if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE) { struct btrfs_root *root = BTRFS_I(rc->data_inode)->root; u64 owning_root_id = btrfs_get_extent_owner_root(fs_info, path->nodes[0], path->slots[0]); root->relocation_src_root = owning_root_id; } if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { ret = add_tree_block(rc, &key, path, &blocks); } else if (rc->stage == UPDATE_DATA_PTRS && (flags & BTRFS_EXTENT_FLAG_DATA)) { ret = add_data_references(rc, &key, path, &blocks); } else { btrfs_release_path(path); ret = 0; } if (ret < 0) { err = ret; break; } if (!RB_EMPTY_ROOT(&blocks)) { ret = relocate_tree_blocks(trans, rc, &blocks); if (ret < 0) { if (ret != -EAGAIN) { err = ret; break; } rc->extents_found--; rc->search_start = key.objectid; } } btrfs_end_transaction_throttle(trans); btrfs_btree_balance_dirty(fs_info); trans = NULL; if (rc->stage == MOVE_DATA_EXTENTS && (flags & BTRFS_EXTENT_FLAG_DATA)) { rc->found_file_extent = true; ret = relocate_data_extent(rc->data_inode, &key, &rc->cluster); if (ret < 0) { err = ret; break; } } if (btrfs_should_cancel_balance(fs_info)) { err = -ECANCELED; break; } } if (trans && progress && err == -ENOSPC) { ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags); if (ret == 1) { err = 0; progress = 0; goto restart; } } btrfs_release_path(path); clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY); if (trans) { btrfs_end_transaction_throttle(trans); btrfs_btree_balance_dirty(fs_info); } if (!err) { ret = relocate_file_extent_cluster(rc->data_inode, &rc->cluster); if (ret < 0) err = ret; } rc->create_reloc_tree = false; set_reloc_control(rc); btrfs_backref_release_cache(&rc->backref_cache); btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL); /* * Even in the case when the relocation is cancelled, we should all go * through prepare_to_merge() and merge_reloc_roots(). * * For error (including cancelled balance), prepare_to_merge() will * mark all reloc trees orphan, then queue them for cleanup in * merge_reloc_roots() */ err = prepare_to_merge(rc, err); merge_reloc_roots(rc); rc->merge_reloc_tree = false; unset_reloc_control(rc); btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL); /* get rid of pinned extents */ trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { err = PTR_ERR(trans); goto out_free; } ret = btrfs_commit_transaction(trans); if (ret && !err) err = ret; out_free: ret = clean_dirty_subvols(rc); if (ret < 0 && !err) err = ret; btrfs_free_block_rsv(fs_info, rc->block_rsv); btrfs_free_path(path); return err; } static int __insert_orphan_inode(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 objectid) { struct btrfs_path *path; struct btrfs_inode_item *item; struct extent_buffer *leaf; int ret; path = btrfs_alloc_path(); if (!path) return -ENOMEM; ret = btrfs_insert_empty_inode(trans, root, path, objectid); if (ret) goto out; leaf = path->nodes[0]; item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item); memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item)); btrfs_set_inode_generation(leaf, item, 1); btrfs_set_inode_size(leaf, item, 0); btrfs_set_inode_mode(leaf, item, S_IFREG | 0600); btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC); btrfs_mark_buffer_dirty(trans, leaf); out: btrfs_free_path(path); return ret; } static void delete_orphan_inode(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 objectid) { struct btrfs_path *path; struct btrfs_key key; int ret = 0; path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = objectid; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(trans, root, &key, path, -1, 1); if (ret) { if (ret > 0) ret = -ENOENT; goto out; } ret = btrfs_del_item(trans, root, path); out: if (ret) btrfs_abort_transaction(trans, ret); btrfs_free_path(path); } /* * helper to create inode for data relocation. * the inode is in data relocation tree and its link count is 0 */ static noinline_for_stack struct inode *create_reloc_inode( struct btrfs_fs_info *fs_info, const struct btrfs_block_group *group) { struct inode *inode = NULL; struct btrfs_trans_handle *trans; struct btrfs_root *root; u64 objectid; int err = 0; root = btrfs_grab_root(fs_info->data_reloc_root); trans = btrfs_start_transaction(root, 6); if (IS_ERR(trans)) { btrfs_put_root(root); return ERR_CAST(trans); } err = btrfs_get_free_objectid(root, &objectid); if (err) goto out; err = __insert_orphan_inode(trans, root, objectid); if (err) goto out; inode = btrfs_iget(fs_info->sb, objectid, root); if (IS_ERR(inode)) { delete_orphan_inode(trans, root, objectid); err = PTR_ERR(inode); inode = NULL; goto out; } BTRFS_I(inode)->index_cnt = group->start; err = btrfs_orphan_add(trans, BTRFS_I(inode)); out: btrfs_put_root(root); btrfs_end_transaction(trans); btrfs_btree_balance_dirty(fs_info); if (err) { iput(inode); inode = ERR_PTR(err); } return inode; } /* * Mark start of chunk relocation that is cancellable. Check if the cancellation * has been requested meanwhile and don't start in that case. * * Return: * 0 success * -EINPROGRESS operation is already in progress, that's probably a bug * -ECANCELED cancellation request was set before the operation started */ static int reloc_chunk_start(struct btrfs_fs_info *fs_info) { if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) { /* This should not happen */ btrfs_err(fs_info, "reloc already running, cannot start"); return -EINPROGRESS; } if (atomic_read(&fs_info->reloc_cancel_req) > 0) { btrfs_info(fs_info, "chunk relocation canceled on start"); /* * On cancel, clear all requests but let the caller mark * the end after cleanup operations. */ atomic_set(&fs_info->reloc_cancel_req, 0); return -ECANCELED; } return 0; } /* * Mark end of chunk relocation that is cancellable and wake any waiters. */ static void reloc_chunk_end(struct btrfs_fs_info *fs_info) { /* Requested after start, clear bit first so any waiters can continue */ if (atomic_read(&fs_info->reloc_cancel_req) > 0) btrfs_info(fs_info, "chunk relocation canceled during operation"); clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags); atomic_set(&fs_info->reloc_cancel_req, 0); } static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info) { struct reloc_control *rc; rc = kzalloc(sizeof(*rc), GFP_NOFS); if (!rc) return NULL; INIT_LIST_HEAD(&rc->reloc_roots); INIT_LIST_HEAD(&rc->dirty_subvol_roots); btrfs_backref_init_cache(fs_info, &rc->backref_cache, true); rc->reloc_root_tree.rb_root = RB_ROOT; spin_lock_init(&rc->reloc_root_tree.lock); extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS); return rc; } static void free_reloc_control(struct reloc_control *rc) { struct mapping_node *node, *tmp; free_reloc_roots(&rc->reloc_roots); rbtree_postorder_for_each_entry_safe(node, tmp, &rc->reloc_root_tree.rb_root, rb_node) kfree(node); kfree(rc); } /* * Print the block group being relocated */ static void describe_relocation(struct btrfs_fs_info *fs_info, struct btrfs_block_group *block_group) { char buf[128] = {'\0'}; btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf)); btrfs_info(fs_info, "relocating block group %llu flags %s", block_group->start, buf); } static const char *stage_to_string(enum reloc_stage stage) { if (stage == MOVE_DATA_EXTENTS) return "move data extents"; if (stage == UPDATE_DATA_PTRS) return "update data pointers"; return "unknown"; } /* * function to relocate all extents in a block group. */ int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start) { struct btrfs_block_group *bg; struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start); struct reloc_control *rc; struct inode *inode; struct btrfs_path *path; int ret; int rw = 0; int err = 0; /* * This only gets set if we had a half-deleted snapshot on mount. We * cannot allow relocation to start while we're still trying to clean up * these pending deletions. */ ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE); if (ret) return ret; /* We may have been woken up by close_ctree, so bail if we're closing. */ if (btrfs_fs_closing(fs_info)) return -EINTR; bg = btrfs_lookup_block_group(fs_info, group_start); if (!bg) return -ENOENT; /* * Relocation of a data block group creates ordered extents. Without * sb_start_write(), we can freeze the filesystem while unfinished * ordered extents are left. Such ordered extents can cause a deadlock * e.g. when syncfs() is waiting for their completion but they can't * finish because they block when joining a transaction, due to the * fact that the freeze locks are being held in write mode. */ if (bg->flags & BTRFS_BLOCK_GROUP_DATA) ASSERT(sb_write_started(fs_info->sb)); if (btrfs_pinned_by_swapfile(fs_info, bg)) { btrfs_put_block_group(bg); return -ETXTBSY; } rc = alloc_reloc_control(fs_info); if (!rc) { btrfs_put_block_group(bg); return -ENOMEM; } ret = reloc_chunk_start(fs_info); if (ret < 0) { err = ret; goto out_put_bg; } rc->extent_root = extent_root; rc->block_group = bg; ret = btrfs_inc_block_group_ro(rc->block_group, true); if (ret) { err = ret; goto out; } rw = 1; path = btrfs_alloc_path(); if (!path) { err = -ENOMEM; goto out; } inode = lookup_free_space_inode(rc->block_group, path); btrfs_free_path(path); if (!IS_ERR(inode)) ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0); else ret = PTR_ERR(inode); if (ret && ret != -ENOENT) { err = ret; goto out; } rc->data_inode = create_reloc_inode(fs_info, rc->block_group); if (IS_ERR(rc->data_inode)) { err = PTR_ERR(rc->data_inode); rc->data_inode = NULL; goto out; } describe_relocation(fs_info, rc->block_group); btrfs_wait_block_group_reservations(rc->block_group); btrfs_wait_nocow_writers(rc->block_group); btrfs_wait_ordered_roots(fs_info, U64_MAX, rc->block_group->start, rc->block_group->length); ret = btrfs_zone_finish(rc->block_group); WARN_ON(ret && ret != -EAGAIN); while (1) { enum reloc_stage finishes_stage; mutex_lock(&fs_info->cleaner_mutex); ret = relocate_block_group(rc); mutex_unlock(&fs_info->cleaner_mutex); if (ret < 0) err = ret; finishes_stage = rc->stage; /* * We may have gotten ENOSPC after we already dirtied some * extents. If writeout happens while we're relocating a * different block group we could end up hitting the * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in * btrfs_reloc_cow_block. Make sure we write everything out * properly so we don't trip over this problem, and then break * out of the loop if we hit an error. */ if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) { ret = btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1); if (ret) err = ret; invalidate_mapping_pages(rc->data_inode->i_mapping, 0, -1); rc->stage = UPDATE_DATA_PTRS; } if (err < 0) goto out; if (rc->extents_found == 0) break; btrfs_info(fs_info, "found %llu extents, stage: %s", rc->extents_found, stage_to_string(finishes_stage)); } WARN_ON(rc->block_group->pinned > 0); WARN_ON(rc->block_group->reserved > 0); WARN_ON(rc->block_group->used > 0); out: if (err && rw) btrfs_dec_block_group_ro(rc->block_group); iput(rc->data_inode); out_put_bg: btrfs_put_block_group(bg); reloc_chunk_end(fs_info); free_reloc_control(rc); return err; } static noinline_for_stack int mark_garbage_root(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_trans_handle *trans; int ret, err; trans = btrfs_start_transaction(fs_info->tree_root, 0); if (IS_ERR(trans)) return PTR_ERR(trans); memset(&root->root_item.drop_progress, 0, sizeof(root->root_item.drop_progress)); btrfs_set_root_drop_level(&root->root_item, 0); btrfs_set_root_refs(&root->root_item, 0); ret = btrfs_update_root(trans, fs_info->tree_root, &root->root_key, &root->root_item); err = btrfs_end_transaction(trans); if (err) return err; return ret; } /* * recover relocation interrupted by system crash. * * this function resumes merging reloc trees with corresponding fs trees. * this is important for keeping the sharing of tree blocks */ int btrfs_recover_relocation(struct btrfs_fs_info *fs_info) { LIST_HEAD(reloc_roots); struct btrfs_key key; struct btrfs_root *fs_root; struct btrfs_root *reloc_root; struct btrfs_path *path; struct extent_buffer *leaf; struct reloc_control *rc = NULL; struct btrfs_trans_handle *trans; int ret; int err = 0; path = btrfs_alloc_path(); if (!path) return -ENOMEM; path->reada = READA_BACK; key.objectid = BTRFS_TREE_RELOC_OBJECTID; key.type = BTRFS_ROOT_ITEM_KEY; key.offset = (u64)-1; while (1) { ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0); if (ret < 0) { err = ret; goto out; } if (ret > 0) { if (path->slots[0] == 0) break; path->slots[0]--; } leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); btrfs_release_path(path); if (key.objectid != BTRFS_TREE_RELOC_OBJECTID || key.type != BTRFS_ROOT_ITEM_KEY) break; reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key); if (IS_ERR(reloc_root)) { err = PTR_ERR(reloc_root); goto out; } set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state); list_add(&reloc_root->root_list, &reloc_roots); if (btrfs_root_refs(&reloc_root->root_item) > 0) { fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false); if (IS_ERR(fs_root)) { ret = PTR_ERR(fs_root); if (ret != -ENOENT) { err = ret; goto out; } ret = mark_garbage_root(reloc_root); if (ret < 0) { err = ret; goto out; } } else { btrfs_put_root(fs_root); } } if (key.offset == 0) break; key.offset--; } btrfs_release_path(path); if (list_empty(&reloc_roots)) goto out; rc = alloc_reloc_control(fs_info); if (!rc) { err = -ENOMEM; goto out; } ret = reloc_chunk_start(fs_info); if (ret < 0) { err = ret; goto out_end; } rc->extent_root = btrfs_extent_root(fs_info, 0); set_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { err = PTR_ERR(trans); goto out_unset; } rc->merge_reloc_tree = true; while (!list_empty(&reloc_roots)) { reloc_root = list_entry(reloc_roots.next, struct btrfs_root, root_list); list_del(&reloc_root->root_list); if (btrfs_root_refs(&reloc_root->root_item) == 0) { list_add_tail(&reloc_root->root_list, &rc->reloc_roots); continue; } fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false); if (IS_ERR(fs_root)) { err = PTR_ERR(fs_root); list_add_tail(&reloc_root->root_list, &reloc_roots); btrfs_end_transaction(trans); goto out_unset; } err = __add_reloc_root(reloc_root); ASSERT(err != -EEXIST); if (err) { list_add_tail(&reloc_root->root_list, &reloc_roots); btrfs_put_root(fs_root); btrfs_end_transaction(trans); goto out_unset; } fs_root->reloc_root = btrfs_grab_root(reloc_root); btrfs_put_root(fs_root); } err = btrfs_commit_transaction(trans); if (err) goto out_unset; merge_reloc_roots(rc); unset_reloc_control(rc); trans = btrfs_join_transaction(rc->extent_root); if (IS_ERR(trans)) { err = PTR_ERR(trans); goto out_clean; } err = btrfs_commit_transaction(trans); out_clean: ret = clean_dirty_subvols(rc); if (ret < 0 && !err) err = ret; out_unset: unset_reloc_control(rc); out_end: reloc_chunk_end(fs_info); free_reloc_control(rc); out: free_reloc_roots(&reloc_roots); btrfs_free_path(path); if (err == 0) { /* cleanup orphan inode in data relocation tree */ fs_root = btrfs_grab_root(fs_info->data_reloc_root); ASSERT(fs_root); err = btrfs_orphan_cleanup(fs_root); btrfs_put_root(fs_root); } return err; } /* * helper to add ordered checksum for data relocation. * * cloning checksum properly handles the nodatasum extents. * it also saves CPU time to re-calculate the checksum. */ int btrfs_reloc_clone_csums(struct btrfs_ordered_extent *ordered) { struct btrfs_inode *inode = BTRFS_I(ordered->inode); struct btrfs_fs_info *fs_info = inode->root->fs_info; u64 disk_bytenr = ordered->file_offset + inode->index_cnt; struct btrfs_root *csum_root = btrfs_csum_root(fs_info, disk_bytenr); LIST_HEAD(list); int ret; ret = btrfs_lookup_csums_list(csum_root, disk_bytenr, disk_bytenr + ordered->num_bytes - 1, &list, 0, false); if (ret) return ret; while (!list_empty(&list)) { struct btrfs_ordered_sum *sums = list_entry(list.next, struct btrfs_ordered_sum, list); list_del_init(&sums->list); /* * We need to offset the new_bytenr based on where the csum is. * We need to do this because we will read in entire prealloc * extents but we may have written to say the middle of the * prealloc extent, so we need to make sure the csum goes with * the right disk offset. * * We can do this because the data reloc inode refers strictly * to the on disk bytes, so we don't have to worry about * disk_len vs real len like with real inodes since it's all * disk length. */ sums->logical = ordered->disk_bytenr + sums->logical - disk_bytenr; btrfs_add_ordered_sum(ordered, sums); } return 0; } int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, const struct extent_buffer *buf, struct extent_buffer *cow) { struct btrfs_fs_info *fs_info = root->fs_info; struct reloc_control *rc; struct btrfs_backref_node *node; int first_cow = 0; int level; int ret = 0; rc = fs_info->reloc_ctl; if (!rc) return 0; BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root)); level = btrfs_header_level(buf); if (btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item)) first_cow = 1; if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID && rc->create_reloc_tree) { WARN_ON(!first_cow && level == 0); node = rc->backref_cache.path[level]; BUG_ON(node->bytenr != buf->start && node->new_bytenr != buf->start); btrfs_backref_drop_node_buffer(node); atomic_inc(&cow->refs); node->eb = cow; node->new_bytenr = cow->start; if (!node->pending) { list_move_tail(&node->list, &rc->backref_cache.pending[level]); node->pending = 1; } if (first_cow) mark_block_processed(rc, node); if (first_cow && level > 0) rc->nodes_relocated += buf->len; } if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) ret = replace_file_extents(trans, rc, root, cow); return ret; } /* * called before creating snapshot. it calculates metadata reservation * required for relocating tree blocks in the snapshot */ void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending, u64 *bytes_to_reserve) { struct btrfs_root *root = pending->root; struct reloc_control *rc = root->fs_info->reloc_ctl; if (!rc || !have_reloc_root(root)) return; if (!rc->merge_reloc_tree) return; root = root->reloc_root; BUG_ON(btrfs_root_refs(&root->root_item) == 0); /* * relocation is in the stage of merging trees. the space * used by merging a reloc tree is twice the size of * relocated tree nodes in the worst case. half for cowing * the reloc tree, half for cowing the fs tree. the space * used by cowing the reloc tree will be freed after the * tree is dropped. if we create snapshot, cowing the fs * tree may use more space than it frees. so we need * reserve extra space. */ *bytes_to_reserve += rc->nodes_relocated; } /* * called after snapshot is created. migrate block reservation * and create reloc root for the newly created snapshot * * This is similar to btrfs_init_reloc_root(), we come out of here with two * references held on the reloc_root, one for root->reloc_root and one for * rc->reloc_roots. */ int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans, struct btrfs_pending_snapshot *pending) { struct btrfs_root *root = pending->root; struct btrfs_root *reloc_root; struct btrfs_root *new_root; struct reloc_control *rc = root->fs_info->reloc_ctl; int ret; if (!rc || !have_reloc_root(root)) return 0; rc = root->fs_info->reloc_ctl; rc->merging_rsv_size += rc->nodes_relocated; if (rc->merge_reloc_tree) { ret = btrfs_block_rsv_migrate(&pending->block_rsv, rc->block_rsv, rc->nodes_relocated, true); if (ret) return ret; } new_root = pending->snap; reloc_root = create_reloc_root(trans, root->reloc_root, new_root->root_key.objectid); if (IS_ERR(reloc_root)) return PTR_ERR(reloc_root); ret = __add_reloc_root(reloc_root); ASSERT(ret != -EEXIST); if (ret) { /* Pairs with create_reloc_root */ btrfs_put_root(reloc_root); return ret; } new_root->reloc_root = btrfs_grab_root(reloc_root); if (rc->create_reloc_tree) ret = clone_backref_node(trans, rc, root, reloc_root); return ret; } /* * Get the current bytenr for the block group which is being relocated. * * Return U64_MAX if no running relocation. */ u64 btrfs_get_reloc_bg_bytenr(const struct btrfs_fs_info *fs_info) { u64 logical = U64_MAX; lockdep_assert_held(&fs_info->reloc_mutex); if (fs_info->reloc_ctl && fs_info->reloc_ctl->block_group) logical = fs_info->reloc_ctl->block_group->start; return logical; }
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